The objective of this work is to demonstrate how the viscoelastic, thermal, rheological, hardness, wear resistance and fracture behavior of bioinert high-density polyethylene （HDPE） can be changed by the addition of...The objective of this work is to demonstrate how the viscoelastic, thermal, rheological, hardness, wear resistance and fracture behavior of bioinert high-density polyethylene （HDPE） can be changed by the addition of hydroxyapatite （HAP） nano particles. Also the effects of accelerated thermal ageing on the composite properties have been investigated. Different weight fractions of HAP nano particles up to 30 wt% have been incorporated in HDPE matrix by using melt blending in co-rotating intermeshing twin screw extruder. The fracture toughness results showed a remarkable decrease in proportion to the HAP content. The differential scanning calorimetry results indicated that the melting temperature and crystallinity were affected by the addition of HAP nano particles into the matrix. The complex viscosity increased as the percentage of HAP increased due to the restriction of the molecular mobility. The dynamic mechanical analysis results revealed that higher storage modulus （8.3 1011 Pa） could be obtained in the developed HDPE/HAP in 30 wt% compared to neat HDPE （5.1 1011 Pa）. Finally, the hardness and wear resistance of HDPE were improved significantly due to the addition of HAP nano particles. The changes in the HDPE and its nano composite properties due to ageing showed that the HDPE and its nano composites crystallinity increased while the fracture toughness, hardness, wear resistance, storage and loss modulus decreased.展开更多
The utilisation of oil palm fibre(OPF)and pineapple leaf fibres(PALF)as reinforcement materials for bio-phenolic composites is growing especially in automotive lightweight applications.The major aim of this current st...The utilisation of oil palm fibre(OPF)and pineapple leaf fibres(PALF)as reinforcement materials for bio-phenolic composites is growing especially in automotive lightweight applications.The major aim of this current study is to investigate the influence of alkali(Ca(OH)_(2)) treatment on pure and hybrid composites.The effects of enhancements in chemical interactions were evaluated by the Fourier-Transform Infrared Spectrometer(FTIR).Dynamic Mechanical Analysis(DMA)and Thermogravimetric Analysis(TGA)performance of untreated reinforcements(OPF and PALF)and treated(OPF/OPF)composites at varying temperature and noted sufficient interfacial bonding contributing towards the improvements in thermal stability.From DMA results,the storage modulus improved with treated composites while the damping factor was reduced.Furthermore,the treated hybrid composites exhibited significant improvements in thermal stability compared to untreated fibre composites.The results indicated that alkali calcium hydroxide(Ca(OH2(:T)incorporation in hybrid composites(OPF/PALF)results in increased tensile strength and modulus among all composites.Similarly,the alkali-treated(Ca(OH)_(2))-treated pure composite(T/50%PALF),and hybrid composites(T/1OPF.1PALF)exhibited better flexural strength as compared with other composites.In contrast,the T/50%PALF showed higher flexural stress of 78.2 MPa,while the flexural modulus was recorded at 6503 MPa.It can be proposed from the findings of this study that the alkali treatment(5%Ca(OH)_(2))can be utilised to improve the strength and efficiency of agriculture biomass to be used as reinforcements in composites.Additionally,the hybridisation of bio-fibre composites has the potential as a novel variety of biodegradable and sustainable composites appropriate for several industrial and engineering applications.展开更多
Cellulose nanocrystal(CNC)is a biomaterial derived from plant lignocellulosic components,widely applied in various industrial fields.Concurrently,with the growth of awareness in developing green nanomaterial,the explo...Cellulose nanocrystal(CNC)is a biomaterial derived from plant lignocellulosic components,widely applied in various industrial fields.Concurrently,with the growth of awareness in developing green nanomaterial,the explored Washingtonia fibre could be alternative biomass for obtaining CNC products.In the present work,different acid concentrations of 5%,15%,and 25%hydrochloric solutions were employed to produce CNCs from Washingtonia fibre.With the chemical treatments,the yield of the CNC product was successfully retained at 21.6%-25.1%.Individually separated and needle-shaped CNC particles could be observed under the microscopic viewing with the increased acid concentrations.From elemental analysis,a relatively pure cellulose compartment was produced for all CNC samples.The zeta potential values between-10 to-16 mV proved that each nanoparticle sample possessed dispersion ability within an aqueous solution.Meanwhile,the degree of crystallinity and the thermal behavior of CNCs were enhanced with the increased acidic concentrations.Hence,the isolated CNCs(with 15%)from Washingtonia fibre lead a CNC with the highest aspect ratio(30).This parameter is so important that these structures show empowering points of view as nanomaterials for reinforced polymer composites,and it could be a reliable nano-filler for the composite fabrication process in the future.展开更多
基金the Deanship of Scientific Research at King Saud University for funding the work through the research group project No.RGP-VPP-133
文摘The objective of this work is to demonstrate how the viscoelastic, thermal, rheological, hardness, wear resistance and fracture behavior of bioinert high-density polyethylene （HDPE） can be changed by the addition of hydroxyapatite （HAP） nano particles. Also the effects of accelerated thermal ageing on the composite properties have been investigated. Different weight fractions of HAP nano particles up to 30 wt% have been incorporated in HDPE matrix by using melt blending in co-rotating intermeshing twin screw extruder. The fracture toughness results showed a remarkable decrease in proportion to the HAP content. The differential scanning calorimetry results indicated that the melting temperature and crystallinity were affected by the addition of HAP nano particles into the matrix. The complex viscosity increased as the percentage of HAP increased due to the restriction of the molecular mobility. The dynamic mechanical analysis results revealed that higher storage modulus （8.3 1011 Pa） could be obtained in the developed HDPE/HAP in 30 wt% compared to neat HDPE （5.1 1011 Pa）. Finally, the hardness and wear resistance of HDPE were improved significantly due to the addition of HAP nano particles. The changes in the HDPE and its nano composite properties due to ageing showed that the HDPE and its nano composites crystallinity increased while the fracture toughness, hardness, wear resistance, storage and loss modulus decreased.
基金This work is funded by Researchers Supporting Project number(RSP-2022R435),King Saud University,Riyadh,Saudi Arabia.
文摘The utilisation of oil palm fibre(OPF)and pineapple leaf fibres(PALF)as reinforcement materials for bio-phenolic composites is growing especially in automotive lightweight applications.The major aim of this current study is to investigate the influence of alkali(Ca(OH)_(2)) treatment on pure and hybrid composites.The effects of enhancements in chemical interactions were evaluated by the Fourier-Transform Infrared Spectrometer(FTIR).Dynamic Mechanical Analysis(DMA)and Thermogravimetric Analysis(TGA)performance of untreated reinforcements(OPF and PALF)and treated(OPF/OPF)composites at varying temperature and noted sufficient interfacial bonding contributing towards the improvements in thermal stability.From DMA results,the storage modulus improved with treated composites while the damping factor was reduced.Furthermore,the treated hybrid composites exhibited significant improvements in thermal stability compared to untreated fibre composites.The results indicated that alkali calcium hydroxide(Ca(OH2(:T)incorporation in hybrid composites(OPF/PALF)results in increased tensile strength and modulus among all composites.Similarly,the alkali-treated(Ca(OH)_(2))-treated pure composite(T/50%PALF),and hybrid composites(T/1OPF.1PALF)exhibited better flexural strength as compared with other composites.In contrast,the T/50%PALF showed higher flexural stress of 78.2 MPa,while the flexural modulus was recorded at 6503 MPa.It can be proposed from the findings of this study that the alkali treatment(5%Ca(OH)_(2))can be utilised to improve the strength and efficiency of agriculture biomass to be used as reinforcements in composites.Additionally,the hybridisation of bio-fibre composites has the potential as a novel variety of biodegradable and sustainable composites appropriate for several industrial and engineering applications.
基金This work is funded by Researchers Supporting Project number(RSP-2021/117)King Saud University,Riyadh,Saudi Arabia.The authors would like to thank the“PHC Utique”program of the French Ministry of Foreign Affairs and Ministry of Higher Education and Researchthe Tunisian Ministry of Higher Education and Scientific Research in the CMCU Project No.18G1132 for the financial support.
文摘Cellulose nanocrystal(CNC)is a biomaterial derived from plant lignocellulosic components,widely applied in various industrial fields.Concurrently,with the growth of awareness in developing green nanomaterial,the explored Washingtonia fibre could be alternative biomass for obtaining CNC products.In the present work,different acid concentrations of 5%,15%,and 25%hydrochloric solutions were employed to produce CNCs from Washingtonia fibre.With the chemical treatments,the yield of the CNC product was successfully retained at 21.6%-25.1%.Individually separated and needle-shaped CNC particles could be observed under the microscopic viewing with the increased acid concentrations.From elemental analysis,a relatively pure cellulose compartment was produced for all CNC samples.The zeta potential values between-10 to-16 mV proved that each nanoparticle sample possessed dispersion ability within an aqueous solution.Meanwhile,the degree of crystallinity and the thermal behavior of CNCs were enhanced with the increased acidic concentrations.Hence,the isolated CNCs(with 15%)from Washingtonia fibre lead a CNC with the highest aspect ratio(30).This parameter is so important that these structures show empowering points of view as nanomaterials for reinforced polymer composites,and it could be a reliable nano-filler for the composite fabrication process in the future.
