Natural rubber(NR)latex is a renewable colloidal dispersion used in medical gloves,coatings,and flexible products.It is known for its excellent elasticity and film-forming ability but is limited by insufficient mechan...Natural rubber(NR)latex is a renewable colloidal dispersion used in medical gloves,coatings,and flexible products.It is known for its excellent elasticity and film-forming ability but is limited by insufficient mechanical robustness and chemical resistance.Incorporating nanofillers,such as graphene oxide(GO),is an effective approach to enhance its performance;however,achieving strong interfacial compatibility between hydrophilic GO and the nonpolar rubber matrix remains challenging.To overcome this issue,a multifunctional interfacial design inspired by mussel adhesion chemistry was developed to construct a hierarchical and cohesive GO network within the NR latex matrix.A tannic acid-based modifier(TM)bearing catechol and thiol groups was synthesized and anchored onto latex particles via hydrogen bonding with surface proteins and phospholipids,enabling subsequentπ-πinteractions and hydrogen bonding with GO nanosheets.This guided the selective self-assembly of GO into a continuous segregated network along the latex particle boundaries.Hierarchical interface reinforcement was achieved through Eu^(3+)ligand coordination.The incorporation of GO and enhancement of interfacial interactions promoted strain-induced crystallization,resulting in increased crystallinity and improved load transfer.The resulting composite film containing 0.5 part per hundred rubber GO and the bioinspired interface exhibited a tensile strength that was 107.8%higher than that of the pure NR latex film,while maintaining an elongation at break of 915%.Tear strength increased by 118.5%,toughness reached 61.7 MJ/m~3,nitrogen permeability decreased by 20.1%,and antibacterial efficiency against both Escherichia coli and Staphylococcus aureus reached 99.9%.The films also exhibited enhanced resistance to organic solvents,acids,and alkalis.This study provides a green and scalable strategy for fabricating high-performance NR latex-based products suitable for medical,protective,and engineering applications.展开更多
Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and...Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.展开更多
The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties...The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties.This study primarily investigated the principal chemical groups and mechanism of action of TDCPS in promoting NRL vulcanization through a comparative analysis.The results indicated that the key functional groups(thioamide and pyridine)in TDCPS synergistically accelerated crosslinking,reducing the vulcanization time by 41.18%compared to the high-ammonia(HA)preservation system.At an optimal TDCPS dosage of 5 mmol·L^(−1),vulcanized films achieved a tensile strength of 34.18 MPa,with a sulfur content of 1.5 phr further improving the strength by 42.26%.TD outperformed the conventional accelerators 2-imidazolidinethione(ETU)and 3-hydroxypyridine(3-Hp)in promoting the crosslinking density and mechanical performance while eliminating ammonia-related environmental risks.This eco-friendly system demonstrates the industrial potential for sustainable rubber production.展开更多
文章以Windows操作系统为例,通过对La Te X比较常用的几种中文编辑方法进行比对分析,系统地提出La Te X编辑中文的解决办法及各自优缺点,解决了国内使用La Te X进行中文编辑排版时所遇到的困难和麻烦,使得La Te X编辑中文变得更加容易轻...文章以Windows操作系统为例,通过对La Te X比较常用的几种中文编辑方法进行比对分析,系统地提出La Te X编辑中文的解决办法及各自优缺点,解决了国内使用La Te X进行中文编辑排版时所遇到的困难和麻烦,使得La Te X编辑中文变得更加容易轻松,具有较好的实用性。展开更多
基金supported by the National Natural Science Foundation of China(No.52303063)。
文摘Natural rubber(NR)latex is a renewable colloidal dispersion used in medical gloves,coatings,and flexible products.It is known for its excellent elasticity and film-forming ability but is limited by insufficient mechanical robustness and chemical resistance.Incorporating nanofillers,such as graphene oxide(GO),is an effective approach to enhance its performance;however,achieving strong interfacial compatibility between hydrophilic GO and the nonpolar rubber matrix remains challenging.To overcome this issue,a multifunctional interfacial design inspired by mussel adhesion chemistry was developed to construct a hierarchical and cohesive GO network within the NR latex matrix.A tannic acid-based modifier(TM)bearing catechol and thiol groups was synthesized and anchored onto latex particles via hydrogen bonding with surface proteins and phospholipids,enabling subsequentπ-πinteractions and hydrogen bonding with GO nanosheets.This guided the selective self-assembly of GO into a continuous segregated network along the latex particle boundaries.Hierarchical interface reinforcement was achieved through Eu^(3+)ligand coordination.The incorporation of GO and enhancement of interfacial interactions promoted strain-induced crystallization,resulting in increased crystallinity and improved load transfer.The resulting composite film containing 0.5 part per hundred rubber GO and the bioinspired interface exhibited a tensile strength that was 107.8%higher than that of the pure NR latex film,while maintaining an elongation at break of 915%.Tear strength increased by 118.5%,toughness reached 61.7 MJ/m~3,nitrogen permeability decreased by 20.1%,and antibacterial efficiency against both Escherichia coli and Staphylococcus aureus reached 99.9%.The films also exhibited enhanced resistance to organic solvents,acids,and alkalis.This study provides a green and scalable strategy for fabricating high-performance NR latex-based products suitable for medical,protective,and engineering applications.
基金financially supported by the National Key Research and Development Program of China(Nos.2022YFC2603500,2022YFC2603502)the Guangzhou Science and Technology Project(No.2024A04J4280).All authors acknowledge the financial support.
文摘Silica aerogels(SAs)impart low density and excellent thermal insulation to polymer systems,yet incorporating hydrophobic SAs into aqueous rubber latex systems remains challenging owing to their poor dispersibility and potential to destabilize the latex.Although previous studies have dispersed SAs in aqueous poly(vinyl alcohol)(PVA),the stability of such dispersions and their effectiveness as bridging media for latex integration have not been thoroughly evaluated,which limits their practical application in latex compounding.This study systematically examined how the surface chemistry governs hydrolytic stability,interfacial behavior,and latex compatibility in PVA-assisted aqueous processing.Two hydrophobic SAs were prepared:ethoxy-modified SA(E-SA)and methyl-modified SA(M-SA).Both initially formed a homogeneous PVA slurry,but E-SA rapidly hydrolyzed its surface—OCH_(2)CH_(3)groups,releasing ethanol,becoming hydrophilic,and undergoing irreversible nanopore collapse.In contrast,M-SA maintains its structural integrity and hydrophobicity because its—Si(CH_(3))_(3)groups are highly resistant to hydrolysis.This divergence dictates the behavior during latex blending.The ethanol released from E-SA disrupts electrostatic and steric stabilization,inducing latex coagulation,whereas M-SA/PVA dispersions preserve colloidal stability across diverse latex systems.As a practical demonstration,M-SA-reinforced chlorosulfonated polyethylene(CSM)rubber latex composites show more than a 50%reduction in thermal conductivity while maintaining chemical resistance,enabling high-performance insulating protective gloves and coatings.This work establishes a critical link between aerogel surface chemistry and aqueous processing stability,providing a mechanistic foundation for the rational design of water-based rubber/silica aerogel composites and next-generation thermal insulation materials.
基金the Ministry of Agriculture and Rural Affairs of Chinathe Department of Science and Technology of the Hainan Province for their support+2 种基金financially supported by the National Key R&D Program of China(No. 2022YFD2301201)Hainan Province Science and Technology Special Fund (No. ZDYF2024XDNY284)Earmarked Fund for China Agriculture Research System (No.CARS-33-JG1)
文摘The thioacetamide derivative(TD)-composite preservation system(TDCPS)exhibits superior preservation effects on natural rubber latex(NRL)and significantly enhances its vulcanization efficiency and mechanical properties.This study primarily investigated the principal chemical groups and mechanism of action of TDCPS in promoting NRL vulcanization through a comparative analysis.The results indicated that the key functional groups(thioamide and pyridine)in TDCPS synergistically accelerated crosslinking,reducing the vulcanization time by 41.18%compared to the high-ammonia(HA)preservation system.At an optimal TDCPS dosage of 5 mmol·L^(−1),vulcanized films achieved a tensile strength of 34.18 MPa,with a sulfur content of 1.5 phr further improving the strength by 42.26%.TD outperformed the conventional accelerators 2-imidazolidinethione(ETU)and 3-hydroxypyridine(3-Hp)in promoting the crosslinking density and mechanical performance while eliminating ammonia-related environmental risks.This eco-friendly system demonstrates the industrial potential for sustainable rubber production.
