In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll ...In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.展开更多
This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (S...This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.展开更多
Although various shape memory polymers(SMPs)or diverse applications have been widely reported,the SMPs based on rubbers have been rarely realized due to the low triggering temperature of rubbers.In another aspect,the ...Although various shape memory polymers(SMPs)or diverse applications have been widely reported,the SMPs based on rubbers have been rarely realized due to the low triggering temperature of rubbers.In another aspect,the SMPs based on sustainable substances are highly desired for the growing shortage in fossil resources.In the present study,we accordingly developed the sustainable SMPs with tunable triggering temperature,based on natural rubber(NR)and ferulic acid(FA)as the raw materials.Specifically,the SMPs are based on a crosslinked network of epoxidized natural rubber(ENR)crosslinked by in situ formed zinc ferulate(ZDF)via oxa-Michael reaction.The excellent shape memory effect(SME)is found in these SMPs,as evidenced by the high fixity/recovery ratio and the tunable triggering temperature.With the incorpora-tion of natural halloysite nanotubes(HNTs),the stress and recovery rate of the SMPs are found to be tunable,which widens the application of this kind of SMPs.The combination of adoption of sustainable raw materials,and the excellent and tunable SME makes these SMPs potentially useful in many applications,such as various actuators and heat-shrinkable package materials.展开更多
文摘In this work,Epoxidized natural rubber/sawdust short fiber(ENR-50/SD)composites at different fiber content(5,10,15 and 20 phr)and size(fine size at 60–100μm and coarse size at 10–20 mm)were prepared using two-roll mill and electrical-hydraulic hot press machine respectively.Curing characteristics,water uptake,tensile,morphological,physical,and thermal properties of the composites were investigated.Results indicated that the scorch time and cure time became shorter whereas torque improved as SD content increase.Though the decline of tensile strength and elongation at break values,modulus,hardness and crosslinking density have shown enhancements with the increasing of SD content.The water uptake percentage of all samples has shown an increasing as SD content increase.However,the low SD content,particularly fine size have presented lower water uptake.The temperature of weight%loss(5 and 50 wt%loss)of 5 phr SD(low content)have recorded higher temperature compared to 20 phr SD(high content)in the rubber composites,which indicated higher thermal stability.The fine size of SD has recorded better overall properties than SD coarse size at same loading in the rubber composites.
文摘This article reports the production of electrospun fibers from blends of poly(lactic acid) (PLA) and epoxidized natural rubber (ENR) solutions. The produced fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). SEM images showed the reduction in fiber size with ENR content of up to 25% in the mixture PLA/ENR. FTIR analysis revealed a possible interaction between carboxylic group of PLA and epoxi group of ENR. Thermal analysis showed the increase of the crystallinity fraction with ENR content and a decrease in thermal stability of eletrospun mats with the addition of ENR. The dynamic mechanical properties showed an enhancement of the stiffness of PLA/ENR blends with the increase of ENR content, which can support the production of interesting materials for tissue engineering based on renewable and biocompatible polymers. The reported properties indicate the possibility to use such fiber mats as potential materials in tissue engineering.
基金This work was supported by the National Natural Science Foundation of China[grant number 51222301],[grant number 51473050],[grant number 51333003]Research Fund for the Doctoral Program of Higher Education of China[grant number 20130172110001]Fundamental Research Funds for the Central Universities[grant number 2014ZG0001].
文摘Although various shape memory polymers(SMPs)or diverse applications have been widely reported,the SMPs based on rubbers have been rarely realized due to the low triggering temperature of rubbers.In another aspect,the SMPs based on sustainable substances are highly desired for the growing shortage in fossil resources.In the present study,we accordingly developed the sustainable SMPs with tunable triggering temperature,based on natural rubber(NR)and ferulic acid(FA)as the raw materials.Specifically,the SMPs are based on a crosslinked network of epoxidized natural rubber(ENR)crosslinked by in situ formed zinc ferulate(ZDF)via oxa-Michael reaction.The excellent shape memory effect(SME)is found in these SMPs,as evidenced by the high fixity/recovery ratio and the tunable triggering temperature.With the incorpora-tion of natural halloysite nanotubes(HNTs),the stress and recovery rate of the SMPs are found to be tunable,which widens the application of this kind of SMPs.The combination of adoption of sustainable raw materials,and the excellent and tunable SME makes these SMPs potentially useful in many applications,such as various actuators and heat-shrinkable package materials.
基金supported by the National Natural Science Foundation of China (51861165203)China Postdoctoral Science Foundation (2019M653398)+1 种基金Sichuan Science and Technology Program (2020YJ0261)Shiyanjia Lab (www.shiyanjia.com) for the support of VSM and XRD test
