A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young’s modulus changed gradually and monotoni...A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young’s modulus changed gradually and monotonically with the polycarbonate content. This effect was tentatively explained as the antiplasticization of the PC which is ascribed to the chain mobility, which permits the PC chains to pack more tightly, to the secondary cross-linking between the PC chains, or to the secondary attachment of bulky side-chains to the PC, thus producing steric hindrance to the rotation of the PC main chains. The experimental values found for the impact strength were intermediate between those of the neat polymers, depending upon the dispersed rubber particles of butadiene in the matrix of SAN (Styrene-Acrylonitrile), and the dispersed PC particles which generally make the ABS more brittle. A maximum value of about 88 KJ/m2 for the impact strength was observed for the blend with 90% PC. This may be attributed to the strong polymer-polymer interactions for this particular composition. The variations in the heat deflection temperature HDT and the Vicat softening point with the blend composition were very similar, and allowed us to assume that the phase inversion between the matrices of the two polymers takes place at 50% PC. The morphology of the blends revealed by SEM observation, show a co-continuous structure.展开更多
Films of polymethyl methacrylate (PMMA)/polycarbonate (PC) polymer blend doped silicon carbide (SiC) nanopowder are synthesized by the casting method. The study for the structural, optical and electrical behavior of P...Films of polymethyl methacrylate (PMMA)/polycarbonate (PC) polymer blend doped silicon carbide (SiC) nanopowder are synthesized by the casting method. The study for the structural, optical and electrical behavior of PMMA/PC blend without and with low contents (≤0.8 wt%) of SiC is done. The change of the structure is investigated from X-ray spectra. After the addition of SiC, the intensity of the main X-ray halo peak at 2θ = 20.26°of PMMA/PC is decreased, attributed to an interaction between PMMA/PC. It’s clear that SiC is causing an increase in the amorphous regions inside the PMMA/PC blend. The peaks related to SiC are not found attributed using a small amount of SiC with complete dissolution of SiC. The shift of the intensity for IR bands has supported an interaction between all components. The values of the optical band gap from UV-Vis spectra using indirect transition are decreased with the increase of SiC. The values of the electrical conductivity are low at low frequency attributed to the charge accumulation at the electrode which takes place. The conductivity is increased as the increase of frequency due to the mobility of charge carriers. Furthermore, the conductivity is increased with the increase of SiC contents. The values of ε' and ε'' are very high at the lower frequency and they decrease when the frequency is increased attributed to the effect. The plot of both Z' and Z'' shows dramatic decrease with the increase of frequency.展开更多
Phosphatidylcholine(PC)and phosphatidylethanolatmine(PE)are successfully separated,meanwhile various components of phosphatidylcholines can also be separated by using the following operating conditions:the Lichrosorb ...Phosphatidylcholine(PC)and phosphatidylethanolatmine(PE)are successfully separated,meanwhile various components of phosphatidylcholines can also be separated by using the following operating conditions:the Lichrosorb Si 60 column(4.6mm×250mmi.d.5μm),hexane:iso-propanol:water:85%phosphate(45:48:7.5:0.15,volume ratio)as mobile phase,40℃,1.0mL/min flow rate and UV detection at 206 nm.This method is very simple,and its recovery and accuracy are very high,so it is especially suitable for the preliminary analysis of phosphatidylcholine components.展开更多
For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the inte...For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region （〈0.1%）. The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends.展开更多
High-pressure crystallization behavior of poly(ethylene terephthalate)(PET)/biphenol-A polycarbonate(PC) blends were investigated by scanning electron microscopy(SEM) and atomic force microscopy(AFM).Two novel spherul...High-pressure crystallization behavior of poly(ethylene terephthalate)(PET)/biphenol-A polycarbonate(PC) blends were investigated by scanning electron microscopy(SEM) and atomic force microscopy(AFM).Two novel spherulitic structures,i.e.bamboo-shoot-like spherulite and brain-like spherulite,were observed in the polyester extended-chain crystals.The extended-chain lamellar crystal may be the substructure of these spherulites.This morphology,which is quite different from that of usual spherulite and extended-chain crystal,may promote the understanding of formation process and mechanism for both polymer spherulites and extended-chain crystals.展开更多
文摘A series of blends of Acrylonitrile-Butadiene-Styrene (ABS) and Polycarbonate (PC) were prepared and some of their thermal and mechanical properties were determined. The Young’s modulus changed gradually and monotonically with the polycarbonate content. This effect was tentatively explained as the antiplasticization of the PC which is ascribed to the chain mobility, which permits the PC chains to pack more tightly, to the secondary cross-linking between the PC chains, or to the secondary attachment of bulky side-chains to the PC, thus producing steric hindrance to the rotation of the PC main chains. The experimental values found for the impact strength were intermediate between those of the neat polymers, depending upon the dispersed rubber particles of butadiene in the matrix of SAN (Styrene-Acrylonitrile), and the dispersed PC particles which generally make the ABS more brittle. A maximum value of about 88 KJ/m2 for the impact strength was observed for the blend with 90% PC. This may be attributed to the strong polymer-polymer interactions for this particular composition. The variations in the heat deflection temperature HDT and the Vicat softening point with the blend composition were very similar, and allowed us to assume that the phase inversion between the matrices of the two polymers takes place at 50% PC. The morphology of the blends revealed by SEM observation, show a co-continuous structure.
文摘Films of polymethyl methacrylate (PMMA)/polycarbonate (PC) polymer blend doped silicon carbide (SiC) nanopowder are synthesized by the casting method. The study for the structural, optical and electrical behavior of PMMA/PC blend without and with low contents (≤0.8 wt%) of SiC is done. The change of the structure is investigated from X-ray spectra. After the addition of SiC, the intensity of the main X-ray halo peak at 2θ = 20.26°of PMMA/PC is decreased, attributed to an interaction between PMMA/PC. It’s clear that SiC is causing an increase in the amorphous regions inside the PMMA/PC blend. The peaks related to SiC are not found attributed using a small amount of SiC with complete dissolution of SiC. The shift of the intensity for IR bands has supported an interaction between all components. The values of the optical band gap from UV-Vis spectra using indirect transition are decreased with the increase of SiC. The values of the electrical conductivity are low at low frequency attributed to the charge accumulation at the electrode which takes place. The conductivity is increased as the increase of frequency due to the mobility of charge carriers. Furthermore, the conductivity is increased with the increase of SiC contents. The values of ε' and ε'' are very high at the lower frequency and they decrease when the frequency is increased attributed to the effect. The plot of both Z' and Z'' shows dramatic decrease with the increase of frequency.
文摘Phosphatidylcholine(PC)and phosphatidylethanolatmine(PE)are successfully separated,meanwhile various components of phosphatidylcholines can also be separated by using the following operating conditions:the Lichrosorb Si 60 column(4.6mm×250mmi.d.5μm),hexane:iso-propanol:water:85%phosphate(45:48:7.5:0.15,volume ratio)as mobile phase,40℃,1.0mL/min flow rate and UV detection at 206 nm.This method is very simple,and its recovery and accuracy are very high,so it is especially suitable for the preliminary analysis of phosphatidylcholine components.
文摘For evaluation of the rheological and mechanical properties of highly filled wood plastic composites （WPCs）, polypropylene/polyethylene （PP/PE） blends were grafted with maleic anhydride （MAH） to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region （〈0.1%）. The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends.
文摘High-pressure crystallization behavior of poly(ethylene terephthalate)(PET)/biphenol-A polycarbonate(PC) blends were investigated by scanning electron microscopy(SEM) and atomic force microscopy(AFM).Two novel spherulitic structures,i.e.bamboo-shoot-like spherulite and brain-like spherulite,were observed in the polyester extended-chain crystals.The extended-chain lamellar crystal may be the substructure of these spherulites.This morphology,which is quite different from that of usual spherulite and extended-chain crystal,may promote the understanding of formation process and mechanism for both polymer spherulites and extended-chain crystals.
