Low density polyethylene(LDPE)/lignin blends were prepared using melt blending.Two kinds of compatibilizers, ethylene-vinylacetate(EVA) which is softer than LDPE and polyethylene grafted with maleic anhydride(PE-g-MA)...Low density polyethylene(LDPE)/lignin blends were prepared using melt blending.Two kinds of compatibilizers, ethylene-vinylacetate(EVA) which is softer than LDPE and polyethylene grafted with maleic anhydride(PE-g-MA) which is harder than LDPE were used to improve the interfacial adhesion.Scanning electron microscope(SEM) was used to investigate the dispersion of lignin in LDPE matrix.The results showed that both of the compatibilizers could improve the interaction between the low density polyethylene and l...展开更多
Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and...Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and three maleic-anhydride-grafted polypropylenes （PP-g-MA） with different melt flow indexes （MFI）, were used to improve the dispersion of organic clay in matrix. On the other hand, the effects of organic montmorillonite （OMMT） content on the nanocomposite structure in terms of clay dispersion in PPR matrix, thermal behavior and tensile properties were also studied. The X-ray diffraction （XRD） and transmission electron microscopy （TEM） results show that the organic clay layers are mainly intercalated and partially exfoliated in the nanocomposites. Moreover, a PP-g-MA compatibilizer （compatibilizer B） having high MFI can greatly increase the interlayer spacing of the clay as compared with other compatibilizers. With the introduction of compatibilizer D （POE-g-MA）, most of the clays are dispersed into the POE phase, and the shape of the dispersed OMMT appears elliptic, which differs from the strip of PP-g-MA. Compared with virgin PPR, the Young＇s modulus of the nanocomposite evidently increases when a compatibilizer C （PP-g-MA） with medium MFI is used. For the nanocomposites with compatibilizer B and C, their crystallinities （Xc） increase as compared with that of the virgin PPR. Furthermore, the increase of OMMT loadings presents little effect on the melt temperature （Tc） of the PPR/OMMT nanocomposites, and slight effect on their crystallization temperature （Tc）. Only compatibilizer B can lead to a marked increases in crystallinity and Tc of the nanocomposite when the OMMT content is 2 wt%.展开更多
Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor mis...Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.展开更多
Donor-acceptor （D-A） type fully conjugated block copolymer systems have been rarely reported due to the challenges in synthetic approaches to prepare well-defined low-polydispersity products. In this work, fully con...Donor-acceptor （D-A） type fully conjugated block copolymer systems have been rarely reported due to the challenges in synthetic approaches to prepare well-defined low-polydispersity products. In this work, fully conjugated block copolymers are synthesized in a one-pot reaction through Stille coupling polycondensation, by utilizing the end-functional polymer copolymerization method. End-functional P3HT are copolymerized with AA （2,7-dihromo-9-（heptadecan-9-yl）-9H- carbazole） and BB （4,7-bis（5-（trimethylstannyl）thiophen-2-yl）benzo[c][1,2,5]thiadiazole, TBT） type monomers, respectively. The orthogonal solubility between the very soluble P3HT donor and the insoluble PCDTBT acceptor block improves the purity of block copolymers as well as distinct nano-scale phase-separation compared with other reports on miscibility of donor and acceptor polymer block. Further purification via preparative GPC is carried out to remove the excess of unreacted P3HT and free PCDTBT as well as to achieve low polydispersity of block copolymers. The chemical structure of the P3HT- b-PCDTBT block copolymers are verified via IH-NMR, and further confirmed by FTIR spectra. The block copolymer shows broad absorption and moderate optical band gap of 1.8 eV. Furthermore, the fully conjugated block copolymer films exhibit significant fine structures, much smoother film morphology compared to P3HT/PCDTBT polymer blends. By adding a small amount of block copolymer P3HT-b-PCDTBT as a compatibilizer into the bulk-heterojunction of P3HT：PC61BM blends, polymer solar ceils with an 8% increase of short circuit current （Jse） and 10% increase of power conversion efficiency （PCE） are achieved owing to the improvement of the active-layer film morphology. To the best of our knowledge, this is the first report on donor-acceptor type fully conjugated block copolymer as an effective ternary additive in polymer： fullerene bulk heterojunction solar cells.展开更多
In this work,the formation of cocontinuous structure in immiscible high density polyethylene/isotactic polypropylene(HDPE/iPP)blends was investigated for various olefin-based compatibilizers of distinct molecular arch...In this work,the formation of cocontinuous structure in immiscible high density polyethylene/isotactic polypropylene(HDPE/iPP)blends was investigated for various olefin-based compatibilizers of distinct molecular architectures,including ternary random copolymer EPDM,olefin block copolymer(OBC),polypropylene-based OBC(PP-OBC),ethylene/a-olefin copolymer(POE),bottlebrush polymer poly(1-dodecene),and comb-like poly(propylene-co-high a-olefin)(PPO).The scanning electron microscopy results show that after adding OBC,PP-OBC,and POE copolymers,the finer droplet-in-matrix morphologies were obtained in 70/30 HDPE/iPP blend.Interestingly,for 70/30 HDPE/iPP blend with just 5 wt%of PPO copolymers,the phase inversion from droplet-in-matrix to cocontinuous morphology can be observed.It was proposed that the development of cocontinuous morphology contained the following steps:(1)in terfacial saturati on of compatibilizers and droplet deformation,(2)droplet-droplet coalesce nee,(3)continuity development,and(4)the formation of dual-phase con tinuity.Among the diverse copolymers studied in this work,PPO copolymer can be easily removed out of the interface during droplet coalescence and stabilize the curvature of minor fiber phase,facilitating the formation of cocontinuous morphology.In contrast,other olefin-based compatibilizers(EPDM,OBC,PP-OBC,and POE)exhibit the distinct steric repulsion effect to prohibit droplet coalescence.Moreover,the cocontinous interval varies with the compatibilizer architectures.Surprisingly,after adding 10 wt%of PPO copolymers,the cocontinuous interval was greatly broadened from HDPE/iPP range of 45/55-60/40 to that of 40/60-70/30.展开更多
In this study, the maleic anhydride （MAH） and styrene （St） dual monomers grafted polypropylene （PP） and poly[styrene-b- （ethylene-co-butylene）-b-styrene] （SEBS）, i.e. PP-g-（MAH-co-St） and SEBS-g-（MAH-co-S...In this study, the maleic anhydride （MAH） and styrene （St） dual monomers grafted polypropylene （PP） and poly[styrene-b- （ethylene-co-butylene）-b-styrene] （SEBS）, i.e. PP-g-（MAH-co-St） and SEBS-g-（MAH-co-St） are prepared as multi-phase compatibilizers and used to compatibilize the PA6/PS/PP/SEBS （70/10/10/10） model quaternary blends. Both PS and SEBS are encapsulated by the hard shell of PP-g-（MAH-co-St） in the dispersed domains （about 2 μm） of the PA6/PS/PP-g-（MAH-co-St）/SEBS （70/10/10/10） quaternary blend. In contrast, inside the dispersed domains （about 1 μm） of the PA6/PS/PP/SEBS-g-（MAH-co-St） （70/10/10/10） quaternary blend, the soft SEBS-g-（MAH-co-St） encapsulates both the hard PS and PP phases and separates them. With increasing the content of the compatibilizers equally, the morphology of the PA6/PS/（PP＋PP-g-（MAH-co-St））/（SEBS＋SEBS-g-（MAH-co-St）） （70/10/10/10） quaternary blends evolves from the soft （SEBS＋SEBS-g-（MAH-co-St）） encapsulating PS and partially encapsulating PP （about 1 μm）, then to PS exclusively encapsulated by the soft SEBS-g-（MAH-co-St） and then separated by PP-g-（MAH-co-St） inside the smaller domains （about 0.6 μm）. This morphology evolution has been well predicted by spreading coefficients and explained by the reaction between the matrix PA6 and the compatibilizers. The quaternary blends compatibilized by more compatibilizers exhibit stronger hierarchical interfacial adhesions and smaller dispersed domain, which results in the further improved mechanical properties. Compared to the uncompatibilized blend, the blend with both 10 wt% PP-g-（MAH-co-St） and 10 wt% SEBS-g-（MAH-co-St） has the best mechanical properties with the stress at break, strain at break and impact failure energy improved significantly by 97%, 71% and 261%, respectively. There is a strong correlation between the structure and property in the blends.展开更多
Two compatibilizers consisting of styrene-acrylonitrile-glycidyl methacrylate (SAG) terpolymer with different contents of glycidyl methacrylate (GMA), SAG-001 (1 wt% of GMA) and SAG-005 (5 wt% of GMA), and styrene-acr...Two compatibilizers consisting of styrene-acrylonitrile-glycidyl methacrylate (SAG) terpolymer with different contents of glycidyl methacrylate (GMA), SAG-001 (1 wt% of GMA) and SAG-005 (5 wt% of GMA), and styrene-acry-lonitrile-maleic anhydride terpolymer (SAM), SAM-002 (2 wt% of maleic anhydride ), were used to evaluate the role of compatibilizers in the PC/ABS alloy in terms of the mechanical properties, thermal stability and phase morphology. The tensile strength of SAG modified PC/ABS alloy slightly increased than that of SAM modified system, but the two compatibilizers barely affected the flexural strength of the system. On the other hand, the impact strength of SAG modified PC/ABS was improved. In addition, the MFR (melt flow index) of the SAG modified PC/ABS alloy reduced, implying that the viscosity or molecular weight of the system increased. The HDT (heat distortion temperature) also improved with SAG modified system. Moreover, the phase morphology of the SAG modified PC/ABS alloys much enhanced than that of SAM modified system. As a consequence, SAG compatibilized PC/ABS alloy showed better properties than those of SAM modified system, suggesting that the reaction between carboxylic or epoxy groups in SAG and terminal carboxyl group in PC would be the main factor to bring the enhancement in the mechanical, thermal and morphological properties of the PC/ABS alloy.展开更多
Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incor...Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incorporating compatibilizers emerges as a viable strategy to diminish interfacial energy and bolster compatibility,ultimately yielding homogeneous products.In this contribution,polar polyolefins featuring metal dynamic cross-linking networks were synthesized by tandem polymerizing ionic cluster type polar monomers and olefins.Subsequent treatment with HCl aqueous solution and esterification with polyester precursors yields high-performance grafted polar polyolefins for mixed polymer compatibilizing.For PP/PC melting blends,adding 5 wt%of graft-modified polyolefin results in tougher blends that surpass the performance of corresponding virgin iPP in elongation at break(εb).Polar polyolefins containing sodium carboxylate groups play a dual role in compatibilizing PET/HDPE blends,acting both as compatibilizers and nucleating agents.Moreover,this strategy enables the production of grafted polyolefins comprising ternary polymers,which can be employed in compatibilizing ternary blends.展开更多
High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted ...High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted SEBS(SEBS-g-MAH)as a compatibilizer.Dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),and mechanical testing demonstrated that SEBS-g-MAH significantly enhanced the compatibility between the polar(PA6,PLA)and nonpolar(PP,PS,SEBS)components.The compatibilizer effectively refined the microstructure,substantially reduced the domain sizes,and blurred the phase boundaries,indicating enhanced interfacial interactions among all the components.The optimal compatibilizer content(15 wt%)notably increased tensile ductility(elongation at break from 5.0%to 23.7%)while maintaining balanced crystallization behavior,despite slightly decreasing modulus.This work not only demonstrates the broad applicability of high-entropy polymer blends as a sustainable strategy for converting complex,unsorted plastic waste into high-performance value-added materials that significantly contribute to plastic upcycling efforts,but also highlights intriguing physical phenomena emerging from such complex polymer systems.展开更多
Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interfac...Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.展开更多
The effect of maleic anhydride grafted styrene-ethylene- buty-lene-styrene block copolymer （SEBS-g-MAH） and in-situ grafting MAH on mechanical, dynamic mechanical properties of wood flour/recycled plastic blends com...The effect of maleic anhydride grafted styrene-ethylene- buty-lene-styrene block copolymer （SEBS-g-MAH） and in-situ grafting MAH on mechanical, dynamic mechanical properties of wood flour/recycled plastic blends composites was investigated. Recycled plastic polypro-pylene （PP）, high-density polyethylene （HDPE） and polystyrene （PS）, were mixed with wood flour in a high speed blender and then extruded by a twin/single screw tandem extruder system to form wood flour/recycled plastic blends composites. Results show that the impact properties of the composites were improved more significantly by using SEBS-g-MAH compatibilizer than by using the mixtures of MAH and DCP via reactive blending in situ. However, contrary results were ob-served on the tensile and flexural properties of the corresponding com-posites. In General, the mechanical properties of composites made from recycled plastic blends were inferior to those made from virgin plastic blends, especially in elongation break. The morphological study verified that the interfacial adhesion or the compatibility of plastic blends with wood flour was improved by adding SEBS-g-MAH or in-situ grafting MAH. A better interfacial bonding between PP, HDPE, PS and wood flour was obtained by in-situ grafting MAH than the addition of SEBS-g-MAH. In-situ grafting MAH can be considered as a potential way of increasing the interfacial compatibility between plastic blends and wood flour. The storage modulus and damping factor of composites were also characterized through dynamic mechanical analysis （DMA）.展开更多
In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was inves...In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy （SEM） results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter （DSC） test and X-ray diffraction （XRD） characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.展开更多
We use a Monte Carlo method to study the phase and interracial behaviors of A-b-B diblocks in a blend of homopolymers, A and B, which are confined between two asymmetric hard and impenetrable walls. Our results show t...We use a Monte Carlo method to study the phase and interracial behaviors of A-b-B diblocks in a blend of homopolymers, A and B, which are confined between two asymmetric hard and impenetrable walls. Our results show that, when the interaction strength is weak, the block copolymers are uniformly distributed in the ternary mixtures under considered concentrations. Under strong interaction strength, distribution region of the block copolymers changes from a single smooth interface to a curved interface or multi-layer interface in the ternary mixtures. Furthermore, our findings show that with increasing volume fraction of A-b-B diblock copolymer （φc）, copolymer profiles broaden while φc ≥ 0.4, a lamellar phase is formed and by further increasing φc, more thinner layers are observed. Moreover, the results show that, with the increase of φc, the phase interface first gradually transforms from plane to a curved surface rather than micelle or lamellar phase while with the increase of the interaction between A and B segments （CAB）, the copolymer chains not only get stretched in the direction perpendicular to the interface, but also are oriented. The simulations also reveal that the difference between symmetric and asymmetric copolymers is negligible in statistics if the lengths of two blocks are comparable.展开更多
Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a ...Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a compatibilizer.The synergistic effects of the two additives on the mechanical,thermal,and morphological properties of the PLA/PBAT blend films were investigated.The influence of TEC content on the plasticized PLA films and the effect of TDI’s presence on the PLA/PBAT blend films were also studied by comparing them with neat PLA.The results showed a pronounced increase in elongation at break of the plasticized PLA films with increasing TEC levels,but a slight reduction in thermal stability.Also,the addition of TEC and TDI to the blend system not only synergistically enhanced the tensile properties and tensile-impact strength of the PLA/PBAT blends,but also affected their crystallinity and cold crystallization rate,a result of the improvement of interfacial interaction between PLA and PBAT,including the enhancement of their chain mobility.The synergy of the plasticization and compatibilization processes led to the improvement of tensile properties,tensile-impact strength,and compatibility of the blends,accelerating cold crystallization without affecting crystallization.展开更多
Polylactide （PLA） films blended with 10 wt% poly（butylene adipate-co-terephthalate） （PBAT） were prepared by using a twin screw extruder in the presence of the nucleating agent of titanium dioxide （TiO2） and th...Polylactide （PLA） films blended with 10 wt% poly（butylene adipate-co-terephthalate） （PBAT） were prepared by using a twin screw extruder in the presence of the nucleating agent of titanium dioxide （TiO2） and the compatibilizers of toluene diisocyanate （TDI） and PLA-grafted-maleic anhydride （PLA-g-MA）. The synergistic effect of the nucleation and compatibilization on the properties and crystallization behavior of the PLA/PBAT （PLB） films was explored. The results showed that the addition of TiO2 significantly enhanced the tensile strength and the impact tensile resistance of the PLB films while slightly decreased its thermal stability. In addition, the compatibilizers of TDI and PLA-g-MA in the system not only affected the crystallinity and cold crystallization process of the PLB films, but also increased the mechanical properties of them due to the improvement of the interracial interaction between PLA and PBAT revealed by the morphological measurement. The synergistic effects of the nucleating agent and the compatibilizer afforded the blend films with increased tensile strength and impact tensile toughness, improved cold crystallization property and Xc.展开更多
The toughened poly(L-lactic acid)/poly(butylene succinate-butylene terephthalate)(PLLA/PBST) blend with enhanced melt strength and excellent low temperature toughness and strength was prepared by melt compounding thro...The toughened poly(L-lactic acid)/poly(butylene succinate-butylene terephthalate)(PLLA/PBST) blend with enhanced melt strength and excellent low temperature toughness and strength was prepared by melt compounding through in situ compatibilization reaction in presence of multifunctional epoxy compound(ADR).The PLLA/PBST blend was an immiscible system,and the compatibility of the PLLA/PBST blend was improved after adding ADR.FTIR and GPC curves confirmed the formation of the PLLA-g-PBST copolymer,which improved the interfacial bonding of the blend and therefore the PLLA/PBST/ADR blend showed excellent melt strength and mechanical properties.For the PLLA/PBST/ADR blend with 70/30 PLLA/PBST content,the complex viscosity increased significantly with increasing ADR content.Moreover,the tensile strength,elongation at break and impact strength all increased obviously with increasing the ADR content.The elongation at break of the blend reached the maximum value of 392.7%,which was 93.2 times that of neat PLLA.And the impact strength of the blend reached the maximum value of 74.7 k J/m~2,which was 21.3 times that of neat PLLA.Interestingly,the PLLA/PBST/ADR blend exhibited excellent lowtemperature toughness and strength.At –20 ℃,the elongation at break of the PLLA/PBST/ADR blend was as high as 93.2%,and the impact strength reached 18.8 k J/m~2.Meanwhile,the tensile strength of the blend at low temperature was also high(64.7 MPa),which was beneficial to the application of PLA in the low temperature field.In addition,the PLLA/PBST/ADR blend maintaind good biodegradability,which was of great significance to the wide application of PLLA.展开更多
Poly(butylene adipate-co-terephthalate) (PBAT) is currently the largest commercial biodegradable plastics with good toughness and film forming properties, whereas, the inferior barrier and mechanical properties hinder...Poly(butylene adipate-co-terephthalate) (PBAT) is currently the largest commercial biodegradable plastics with good toughness and film forming properties, whereas, the inferior barrier and mechanical properties hinder its applications. Biodegradable poly(propylene carbonate) (PPC) with excellent barrier properties and high strength is a natural choice to address above issue. However, it is challenging to improve the compatibility of these two polymers. Herein, we prepared a reactive compatibilizer with double bond side group through terpolymerization of CO_(2)/propylene oxide/glycidyl methacrylate to enhance the properties of PBAT/PPC blends. Upon addition of 1 wt% compatibilizer, the PBAT/PPC blends (75/25, W/W) showed an increased water vapor barrier property changed from 424 g·m^(−2)·d^(−1) to 204 g·m^(−2)·d^(−1) compared to the control sample. Moreover, the tensile strength and elongation at break increased from 24.7 MPa to 30.3 MPa and from 858% to 1142%, respectively. The PBAT/PPC composite also displayed excellent biodegradability under composting conditions, as confirmed by the significantly decreased molecular weight. The present work provides an efficient way to barrier biodegradable film from PBAT of practical utilization.展开更多
In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly...In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.展开更多
One-step reaction compatibilized microfibrillar reinforced iPP/PET blends （CMRB） were successfully prepared through a ＂slit extrusion-hot stretching-quenching＂ process. Crystallization behavior and morphology of C...One-step reaction compatibilized microfibrillar reinforced iPP/PET blends （CMRB） were successfully prepared through a ＂slit extrusion-hot stretching-quenching＂ process. Crystallization behavior and morphology of CMRB were systematically investigated. Scanning electronic microscopy （SEM） observations showed blurry interface of compatibilized common blend （CCB）. The crystallization behavior of neat iPP, CCB, microfibrillar reinforced iPP/PET blend （MRB） and CMRB was investigated by differential scanning calorimetry （DSC） and polarized optical microscopy （POM）. The increase of crystallization temperature and crystallization rate during nonisothermal crystallization process indicated both PET particles and mierofibrils could serve as nucleating agents and PET microfibrils exhibited higher heterogeneous nucleation ability, which were also vividly revealed by results of POM. Compared with MRB sample, CMRB sample has lower crystallization temperature due to existence of PET microfibrils with smaller aspect ratio and wider distribution. In addition, since in situ compatibilizer tends to stay in the interphase, it could also hinder the diffusion ofiPP molecules to the surface of PET phase, leading to decrease of crystallization rate. Two-dimensional wide-angle X-ray diffi：action （2D-WAXD） was preformed to characterize the crystalline structure of the samples by injection molding, and it was found that well-developed PET microfibrils contained in MRB sample promoted formation of t-phase of/PP.展开更多
A side-chain liquid crystalline ionomer（SLCI） was synthesized by grafting copolymerization of 4-（4-ethoxybenzoyloxy）-4＇-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blend...A side-chain liquid crystalline ionomer（SLCI） was synthesized by grafting copolymerization of 4-（4-ethoxybenzoyloxy）-4＇-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blended with polypropylene（PP） and polybutylene terephthalate（PBT） by melt mixing. The thermal behavior, liquid crystalline properties, morphological structure, and mechanical properties of the blends were investigated by differential scanning calorimetry（DSC）, polarizing optical microscopy（POM）, scanning electron microscopy（SEM）, and tensile measurement. When a proper amount of SLCI was added, fine configurations were formed in the PBT/PP/SLCI blend system, and the mechanical properties were improved due to improved adhesion at the interface. When excess SLCI was added, an inhomogeneous structure resulted, which caused the mechanical properties to deteriorate.展开更多
基金supported by the National Natural Science Foundation of China(Nos.50533050,20634050)
文摘Low density polyethylene(LDPE)/lignin blends were prepared using melt blending.Two kinds of compatibilizers, ethylene-vinylacetate(EVA) which is softer than LDPE and polyethylene grafted with maleic anhydride(PE-g-MA) which is harder than LDPE were used to improve the interfacial adhesion.Scanning electron microscope(SEM) was used to investigate the dispersion of lignin in LDPE matrix.The results showed that both of the compatibilizers could improve the interaction between the low density polyethylene and l...
基金supported by the National Basic Research Program of China(No.2005CB623800)Joint Research Fund for Overseas Chinese Young Scholars(No.50728302)the Program for Zhejiang Provincial Innovative Research Team (No.2009R50004)
文摘Ethylene/propylene-random-copolymer （PPR）/clay nanocomposites were prepared by two-stage melt blending. Four types of compatibilizers, including an ethylene-octene copolymer grafted maleic anhydride （POE-g-MA） and three maleic-anhydride-grafted polypropylenes （PP-g-MA） with different melt flow indexes （MFI）, were used to improve the dispersion of organic clay in matrix. On the other hand, the effects of organic montmorillonite （OMMT） content on the nanocomposite structure in terms of clay dispersion in PPR matrix, thermal behavior and tensile properties were also studied. The X-ray diffraction （XRD） and transmission electron microscopy （TEM） results show that the organic clay layers are mainly intercalated and partially exfoliated in the nanocomposites. Moreover, a PP-g-MA compatibilizer （compatibilizer B） having high MFI can greatly increase the interlayer spacing of the clay as compared with other compatibilizers. With the introduction of compatibilizer D （POE-g-MA）, most of the clays are dispersed into the POE phase, and the shape of the dispersed OMMT appears elliptic, which differs from the strip of PP-g-MA. Compared with virgin PPR, the Young＇s modulus of the nanocomposite evidently increases when a compatibilizer C （PP-g-MA） with medium MFI is used. For the nanocomposites with compatibilizer B and C, their crystallinities （Xc） increase as compared with that of the virgin PPR. Furthermore, the increase of OMMT loadings presents little effect on the melt temperature （Tc） of the PPR/OMMT nanocomposites, and slight effect on their crystallization temperature （Tc）. Only compatibilizer B can lead to a marked increases in crystallinity and Tc of the nanocomposite when the OMMT content is 2 wt%.
基金the National Natural Science Foundation of China (No. 51633003) for the financial support
文摘Polyamide/acrylonitrile-butadiene-styrene copolymer(PA/ABS) blends have drawn considerable attention from both academia and industry for their important applications in automotive and electronic areas. Due to poor miscibility of PA and ABS, developing an effective compatibilization strategy has been an urgent challenge to achieve prominent mechanical properties. In this study, we create a set of mechanically enhanced PA6/ABS blends using two multi-monomer melt-grafted compatibilizers, SEBSg-(MAH-co-St) and ABS-g-(MAH-co-St). The dispersed domain size is significantly decreased and meanwhile the unique "soft shell-encapsulating-hard core" structures form in the presence of compatibilizers. The optimum mechanical performances manifest an increase of 36% in tensile strength and an increase of 1300% in impact strength, compared with the neat PA6/ABS binary blend.
基金financially supported by the National Natural Science Foundation of China(No.21304047)Natural Science Foundation of Jiangsu Province(No.13KJB430017)+1 种基金Research Fund for the Doctoral Program of Higher Education(No.20133221120015)Synergetic Innovation Center for Organic Electronics and Information Displays
文摘Donor-acceptor （D-A） type fully conjugated block copolymer systems have been rarely reported due to the challenges in synthetic approaches to prepare well-defined low-polydispersity products. In this work, fully conjugated block copolymers are synthesized in a one-pot reaction through Stille coupling polycondensation, by utilizing the end-functional polymer copolymerization method. End-functional P3HT are copolymerized with AA （2,7-dihromo-9-（heptadecan-9-yl）-9H- carbazole） and BB （4,7-bis（5-（trimethylstannyl）thiophen-2-yl）benzo[c][1,2,5]thiadiazole, TBT） type monomers, respectively. The orthogonal solubility between the very soluble P3HT donor and the insoluble PCDTBT acceptor block improves the purity of block copolymers as well as distinct nano-scale phase-separation compared with other reports on miscibility of donor and acceptor polymer block. Further purification via preparative GPC is carried out to remove the excess of unreacted P3HT and free PCDTBT as well as to achieve low polydispersity of block copolymers. The chemical structure of the P3HT- b-PCDTBT block copolymers are verified via IH-NMR, and further confirmed by FTIR spectra. The block copolymer shows broad absorption and moderate optical band gap of 1.8 eV. Furthermore, the fully conjugated block copolymer films exhibit significant fine structures, much smoother film morphology compared to P3HT/PCDTBT polymer blends. By adding a small amount of block copolymer P3HT-b-PCDTBT as a compatibilizer into the bulk-heterojunction of P3HT：PC61BM blends, polymer solar ceils with an 8% increase of short circuit current （Jse） and 10% increase of power conversion efficiency （PCE） are achieved owing to the improvement of the active-layer film morphology. To the best of our knowledge, this is the first report on donor-acceptor type fully conjugated block copolymer as an effective ternary additive in polymer： fullerene bulk heterojunction solar cells.
基金the National Natural Science Foundation of China(No.21574097).
文摘In this work,the formation of cocontinuous structure in immiscible high density polyethylene/isotactic polypropylene(HDPE/iPP)blends was investigated for various olefin-based compatibilizers of distinct molecular architectures,including ternary random copolymer EPDM,olefin block copolymer(OBC),polypropylene-based OBC(PP-OBC),ethylene/a-olefin copolymer(POE),bottlebrush polymer poly(1-dodecene),and comb-like poly(propylene-co-high a-olefin)(PPO).The scanning electron microscopy results show that after adding OBC,PP-OBC,and POE copolymers,the finer droplet-in-matrix morphologies were obtained in 70/30 HDPE/iPP blend.Interestingly,for 70/30 HDPE/iPP blend with just 5 wt%of PPO copolymers,the phase inversion from droplet-in-matrix to cocontinuous morphology can be observed.It was proposed that the development of cocontinuous morphology contained the following steps:(1)in terfacial saturati on of compatibilizers and droplet deformation,(2)droplet-droplet coalesce nee,(3)continuity development,and(4)the formation of dual-phase con tinuity.Among the diverse copolymers studied in this work,PPO copolymer can be easily removed out of the interface during droplet coalescence and stabilize the curvature of minor fiber phase,facilitating the formation of cocontinuous morphology.In contrast,other olefin-based compatibilizers(EPDM,OBC,PP-OBC,and POE)exhibit the distinct steric repulsion effect to prohibit droplet coalescence.Moreover,the cocontinous interval varies with the compatibilizer architectures.Surprisingly,after adding 10 wt%of PPO copolymers,the cocontinuous interval was greatly broadened from HDPE/iPP range of 45/55-60/40 to that of 40/60-70/30.
基金financially supported by the National Natural Science Foundation of China (No. 51633003)State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology (No. OIC-201601006)
文摘In this study, the maleic anhydride （MAH） and styrene （St） dual monomers grafted polypropylene （PP） and poly[styrene-b- （ethylene-co-butylene）-b-styrene] （SEBS）, i.e. PP-g-（MAH-co-St） and SEBS-g-（MAH-co-St） are prepared as multi-phase compatibilizers and used to compatibilize the PA6/PS/PP/SEBS （70/10/10/10） model quaternary blends. Both PS and SEBS are encapsulated by the hard shell of PP-g-（MAH-co-St） in the dispersed domains （about 2 μm） of the PA6/PS/PP-g-（MAH-co-St）/SEBS （70/10/10/10） quaternary blend. In contrast, inside the dispersed domains （about 1 μm） of the PA6/PS/PP/SEBS-g-（MAH-co-St） （70/10/10/10） quaternary blend, the soft SEBS-g-（MAH-co-St） encapsulates both the hard PS and PP phases and separates them. With increasing the content of the compatibilizers equally, the morphology of the PA6/PS/（PP＋PP-g-（MAH-co-St））/（SEBS＋SEBS-g-（MAH-co-St）） （70/10/10/10） quaternary blends evolves from the soft （SEBS＋SEBS-g-（MAH-co-St）） encapsulating PS and partially encapsulating PP （about 1 μm）, then to PS exclusively encapsulated by the soft SEBS-g-（MAH-co-St） and then separated by PP-g-（MAH-co-St） inside the smaller domains （about 0.6 μm）. This morphology evolution has been well predicted by spreading coefficients and explained by the reaction between the matrix PA6 and the compatibilizers. The quaternary blends compatibilized by more compatibilizers exhibit stronger hierarchical interfacial adhesions and smaller dispersed domain, which results in the further improved mechanical properties. Compared to the uncompatibilized blend, the blend with both 10 wt% PP-g-（MAH-co-St） and 10 wt% SEBS-g-（MAH-co-St） has the best mechanical properties with the stress at break, strain at break and impact failure energy improved significantly by 97%, 71% and 261%, respectively. There is a strong correlation between the structure and property in the blends.
文摘Two compatibilizers consisting of styrene-acrylonitrile-glycidyl methacrylate (SAG) terpolymer with different contents of glycidyl methacrylate (GMA), SAG-001 (1 wt% of GMA) and SAG-005 (5 wt% of GMA), and styrene-acry-lonitrile-maleic anhydride terpolymer (SAM), SAM-002 (2 wt% of maleic anhydride ), were used to evaluate the role of compatibilizers in the PC/ABS alloy in terms of the mechanical properties, thermal stability and phase morphology. The tensile strength of SAG modified PC/ABS alloy slightly increased than that of SAM modified system, but the two compatibilizers barely affected the flexural strength of the system. On the other hand, the impact strength of SAG modified PC/ABS was improved. In addition, the MFR (melt flow index) of the SAG modified PC/ABS alloy reduced, implying that the viscosity or molecular weight of the system increased. The HDT (heat distortion temperature) also improved with SAG modified system. Moreover, the phase morphology of the SAG modified PC/ABS alloys much enhanced than that of SAM modified system. As a consequence, SAG compatibilized PC/ABS alloy showed better properties than those of SAM modified system, suggesting that the reaction between carboxylic or epoxy groups in SAG and terminal carboxyl group in PC would be the main factor to bring the enhancement in the mechanical, thermal and morphological properties of the PC/ABS alloy.
基金supported by National Key R&D Program of China(No.2021YFA1501700)National Natural Science Foundation of China(No.52373002).
文摘Comprehensive Summary:Recycling polyolefin and other plastic mixtures encounters significant obstacles due to the intricate nature and economic inefficiencies of physically separating vast streams of mixed waste.Incorporating compatibilizers emerges as a viable strategy to diminish interfacial energy and bolster compatibility,ultimately yielding homogeneous products.In this contribution,polar polyolefins featuring metal dynamic cross-linking networks were synthesized by tandem polymerizing ionic cluster type polar monomers and olefins.Subsequent treatment with HCl aqueous solution and esterification with polyester precursors yields high-performance grafted polar polyolefins for mixed polymer compatibilizing.For PP/PC melting blends,adding 5 wt%of graft-modified polyolefin results in tougher blends that surpass the performance of corresponding virgin iPP in elongation at break(εb).Polar polyolefins containing sodium carboxylate groups play a dual role in compatibilizing PET/HDPE blends,acting both as compatibilizers and nucleating agents.Moreover,this strategy enables the production of grafted polyolefins comprising ternary polymers,which can be employed in compatibilizing ternary blends.
基金supported by the National Natural Science Foundation of China(No.52173017)the Project of Introducing Urgently Needed and Scarce Talents in Key Supported Regions of Shandong Province in 2024.
文摘High-entropy polymer blends composed of polypropylene(PP),polystyrene(PS),polyamide 6(PA6),poly(lactic acid)(PLA),and styrene-ethylene-butylene-styrene(SEBS)were successfully fabricated using maleic anhydride-grafted SEBS(SEBS-g-MAH)as a compatibilizer.Dynamic mechanical analysis(DMA),differential scanning calorimetry(DSC),scanning electron microscopy(SEM),and mechanical testing demonstrated that SEBS-g-MAH significantly enhanced the compatibility between the polar(PA6,PLA)and nonpolar(PP,PS,SEBS)components.The compatibilizer effectively refined the microstructure,substantially reduced the domain sizes,and blurred the phase boundaries,indicating enhanced interfacial interactions among all the components.The optimal compatibilizer content(15 wt%)notably increased tensile ductility(elongation at break from 5.0%to 23.7%)while maintaining balanced crystallization behavior,despite slightly decreasing modulus.This work not only demonstrates the broad applicability of high-entropy polymer blends as a sustainable strategy for converting complex,unsorted plastic waste into high-performance value-added materials that significantly contribute to plastic upcycling efforts,but also highlights intriguing physical phenomena emerging from such complex polymer systems.
基金financially supported by the National Natural Science Foundation of China(Nos.22172028,21903015,and 22403017)Natural Science Foundation of Fujian Province of China(No.2022J05041)。
文摘Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.
基金supported by the National High Technology Research and Development Program of China(2010AA101703)the Natural Science Foundation of Heilongjiang Province of China (C200950)the Fundamental Research Fundsfor the Central Universities (DL09BB38)
文摘The effect of maleic anhydride grafted styrene-ethylene- buty-lene-styrene block copolymer （SEBS-g-MAH） and in-situ grafting MAH on mechanical, dynamic mechanical properties of wood flour/recycled plastic blends composites was investigated. Recycled plastic polypro-pylene （PP）, high-density polyethylene （HDPE） and polystyrene （PS）, were mixed with wood flour in a high speed blender and then extruded by a twin/single screw tandem extruder system to form wood flour/recycled plastic blends composites. Results show that the impact properties of the composites were improved more significantly by using SEBS-g-MAH compatibilizer than by using the mixtures of MAH and DCP via reactive blending in situ. However, contrary results were ob-served on the tensile and flexural properties of the corresponding com-posites. In General, the mechanical properties of composites made from recycled plastic blends were inferior to those made from virgin plastic blends, especially in elongation break. The morphological study verified that the interfacial adhesion or the compatibility of plastic blends with wood flour was improved by adding SEBS-g-MAH or in-situ grafting MAH. A better interfacial bonding between PP, HDPE, PS and wood flour was obtained by in-situ grafting MAH than the addition of SEBS-g-MAH. In-situ grafting MAH can be considered as a potential way of increasing the interfacial compatibility between plastic blends and wood flour. The storage modulus and damping factor of composites were also characterized through dynamic mechanical analysis （DMA）.
文摘In-situ reactive compatibilization of high-density polyethylene （HDPE）/ground tire rubber （GTR） blends by dicumyl peroxide （DCP） and HY-2045 - a kind of thermoplastic phenolic resin without catalyst was investigated by studying the mor-phology, stress and strain behavior, dynamic mechanical properties and crystallization performance of the blends. Scanning e-lectron microscopy （SEM） results show that there are a lot of fibrous materials distributing in the interface, which connects the dispersed phase with the matrix and obtains better interfacial strength for prominent mechanical properties. The addition of compatibilizers results in the decrease of crystallinity of the blends and the disappearance of an obvious yield phenomenon, which was proved by the differential scanning calorimeter （DSC） test and X-ray diffraction （XRD） characterization Although the crystallinity of the blends decreases,the tensile strength and tensile strain of the blends significantly increases, especially for the HDPE/GTR/DCP/HY-2045 blends, which is possibly attributed to the good compatibility of the blends owing to the in-situ interface crosslinking. In addition, it is found that the compatibilizing HDPE/GTR blends shows a higher tan^ peak temperature and a broaden transition peak for GTR phase.
基金supported by the National Natural Science Foundation of China(Nos.21304097,21334007and 21674113)
文摘We use a Monte Carlo method to study the phase and interracial behaviors of A-b-B diblocks in a blend of homopolymers, A and B, which are confined between two asymmetric hard and impenetrable walls. Our results show that, when the interaction strength is weak, the block copolymers are uniformly distributed in the ternary mixtures under considered concentrations. Under strong interaction strength, distribution region of the block copolymers changes from a single smooth interface to a curved interface or multi-layer interface in the ternary mixtures. Furthermore, our findings show that with increasing volume fraction of A-b-B diblock copolymer （φc）, copolymer profiles broaden while φc ≥ 0.4, a lamellar phase is formed and by further increasing φc, more thinner layers are observed. Moreover, the results show that, with the increase of φc, the phase interface first gradually transforms from plane to a curved surface rather than micelle or lamellar phase while with the increase of the interaction between A and B segments （CAB）, the copolymer chains not only get stretched in the direction perpendicular to the interface, but also are oriented. The simulations also reveal that the difference between symmetric and asymmetric copolymers is negligible in statistics if the lengths of two blocks are comparable.
基金financially supported by Development and Promotion of Science and Technology Talents (DPST) (No. 013/2559)
文摘Polylactide(PLA)films blended with poly(butylene adipate-co-terephthalate)(PBAT)were hot melted using a twin screw extruder with the addition of triethyl citrate(TEC)as a plasticizer and toluene diisocyanate(TDI)as a compatibilizer.The synergistic effects of the two additives on the mechanical,thermal,and morphological properties of the PLA/PBAT blend films were investigated.The influence of TEC content on the plasticized PLA films and the effect of TDI’s presence on the PLA/PBAT blend films were also studied by comparing them with neat PLA.The results showed a pronounced increase in elongation at break of the plasticized PLA films with increasing TEC levels,but a slight reduction in thermal stability.Also,the addition of TEC and TDI to the blend system not only synergistically enhanced the tensile properties and tensile-impact strength of the PLA/PBAT blends,but also affected their crystallinity and cold crystallization rate,a result of the improvement of interfacial interaction between PLA and PBAT,including the enhancement of their chain mobility.The synergy of the plasticization and compatibilization processes led to the improvement of tensile properties,tensile-impact strength,and compatibility of the blends,accelerating cold crystallization without affecting crystallization.
基金financially supported by the Prince of Songkla University(No.SCI570376S)the Development and Promotion of Science and Technology Talents project(DPST)
文摘Polylactide （PLA） films blended with 10 wt% poly（butylene adipate-co-terephthalate） （PBAT） were prepared by using a twin screw extruder in the presence of the nucleating agent of titanium dioxide （TiO2） and the compatibilizers of toluene diisocyanate （TDI） and PLA-grafted-maleic anhydride （PLA-g-MA）. The synergistic effect of the nucleation and compatibilization on the properties and crystallization behavior of the PLA/PBAT （PLB） films was explored. The results showed that the addition of TiO2 significantly enhanced the tensile strength and the impact tensile resistance of the PLB films while slightly decreased its thermal stability. In addition, the compatibilizers of TDI and PLA-g-MA in the system not only affected the crystallinity and cold crystallization process of the PLB films, but also increased the mechanical properties of them due to the improvement of the interracial interaction between PLA and PBAT revealed by the morphological measurement. The synergistic effects of the nucleating agent and the compatibilizer afforded the blend films with increased tensile strength and impact tensile toughness, improved cold crystallization property and Xc.
基金financially supported by the Science and Technology Development Plan of Jilin Province (No. 20210203199SF)。
文摘The toughened poly(L-lactic acid)/poly(butylene succinate-butylene terephthalate)(PLLA/PBST) blend with enhanced melt strength and excellent low temperature toughness and strength was prepared by melt compounding through in situ compatibilization reaction in presence of multifunctional epoxy compound(ADR).The PLLA/PBST blend was an immiscible system,and the compatibility of the PLLA/PBST blend was improved after adding ADR.FTIR and GPC curves confirmed the formation of the PLLA-g-PBST copolymer,which improved the interfacial bonding of the blend and therefore the PLLA/PBST/ADR blend showed excellent melt strength and mechanical properties.For the PLLA/PBST/ADR blend with 70/30 PLLA/PBST content,the complex viscosity increased significantly with increasing ADR content.Moreover,the tensile strength,elongation at break and impact strength all increased obviously with increasing the ADR content.The elongation at break of the blend reached the maximum value of 392.7%,which was 93.2 times that of neat PLLA.And the impact strength of the blend reached the maximum value of 74.7 k J/m~2,which was 21.3 times that of neat PLLA.Interestingly,the PLLA/PBST/ADR blend exhibited excellent lowtemperature toughness and strength.At –20 ℃,the elongation at break of the PLLA/PBST/ADR blend was as high as 93.2%,and the impact strength reached 18.8 k J/m~2.Meanwhile,the tensile strength of the blend at low temperature was also high(64.7 MPa),which was beneficial to the application of PLA in the low temperature field.In addition,the PLLA/PBST/ADR blend maintaind good biodegradability,which was of great significance to the wide application of PLLA.
基金supported by National Key Research and Development Program of China (No. 2021YFD1700700).
文摘Poly(butylene adipate-co-terephthalate) (PBAT) is currently the largest commercial biodegradable plastics with good toughness and film forming properties, whereas, the inferior barrier and mechanical properties hinder its applications. Biodegradable poly(propylene carbonate) (PPC) with excellent barrier properties and high strength is a natural choice to address above issue. However, it is challenging to improve the compatibility of these two polymers. Herein, we prepared a reactive compatibilizer with double bond side group through terpolymerization of CO_(2)/propylene oxide/glycidyl methacrylate to enhance the properties of PBAT/PPC blends. Upon addition of 1 wt% compatibilizer, the PBAT/PPC blends (75/25, W/W) showed an increased water vapor barrier property changed from 424 g·m^(−2)·d^(−1) to 204 g·m^(−2)·d^(−1) compared to the control sample. Moreover, the tensile strength and elongation at break increased from 24.7 MPa to 30.3 MPa and from 858% to 1142%, respectively. The PBAT/PPC composite also displayed excellent biodegradability under composting conditions, as confirmed by the significantly decreased molecular weight. The present work provides an efficient way to barrier biodegradable film from PBAT of practical utilization.
文摘In this work, polypropylene (PP)/polystyrene (PS) blends with different organoclay concentrations were prepared via melt compounding. Differing from the results of previous reports, the organoclay platelets are mostly located in the dispersed PS phase instead of the interface. The dimensions of the dispersed PS droplets are greatly reduced and apparent compatibilization effect still exists, which cannot be explained by the traditional compatibilization mechanism. A novel compatibilization mecha- nism, "cutting" to apparently compatibilize the immiscible PP/PS blends was proposed. The organoclay platelets tend to form a special "knife-like structure" in the PS domain under the shear stress of the continuous PP phase during compounding. The "clay knife" can split the dispersed PS domain apart and lead to the dramatic reduction of the dispersed domain size.
基金financially supported by National Natural Science Foundation of China(No.20776087)National Programs for High Technology Research and Development of China(No.2008AA03Z510)
文摘One-step reaction compatibilized microfibrillar reinforced iPP/PET blends （CMRB） were successfully prepared through a ＂slit extrusion-hot stretching-quenching＂ process. Crystallization behavior and morphology of CMRB were systematically investigated. Scanning electronic microscopy （SEM） observations showed blurry interface of compatibilized common blend （CCB）. The crystallization behavior of neat iPP, CCB, microfibrillar reinforced iPP/PET blend （MRB） and CMRB was investigated by differential scanning calorimetry （DSC） and polarized optical microscopy （POM）. The increase of crystallization temperature and crystallization rate during nonisothermal crystallization process indicated both PET particles and mierofibrils could serve as nucleating agents and PET microfibrils exhibited higher heterogeneous nucleation ability, which were also vividly revealed by results of POM. Compared with MRB sample, CMRB sample has lower crystallization temperature due to existence of PET microfibrils with smaller aspect ratio and wider distribution. In addition, since in situ compatibilizer tends to stay in the interphase, it could also hinder the diffusion ofiPP molecules to the surface of PET phase, leading to decrease of crystallization rate. Two-dimensional wide-angle X-ray diffi：action （2D-WAXD） was preformed to characterize the crystalline structure of the samples by injection molding, and it was found that well-developed PET microfibrils contained in MRB sample promoted formation of t-phase of/PP.
基金Supported by the National Natural Science Foundation of China(No50673105)
文摘A side-chain liquid crystalline ionomer（SLCI） was synthesized by grafting copolymerization of 4-（4-ethoxybenzoyloxy）-4＇-allyloxybiphenyl and N-allyl-pyridium bromide on polymethylhydrosiloxane. The SLCI was blended with polypropylene（PP） and polybutylene terephthalate（PBT） by melt mixing. The thermal behavior, liquid crystalline properties, morphological structure, and mechanical properties of the blends were investigated by differential scanning calorimetry（DSC）, polarizing optical microscopy（POM）, scanning electron microscopy（SEM）, and tensile measurement. When a proper amount of SLCI was added, fine configurations were formed in the PBT/PP/SLCI blend system, and the mechanical properties were improved due to improved adhesion at the interface. When excess SLCI was added, an inhomogeneous structure resulted, which caused the mechanical properties to deteriorate.
