Design and preparation of a crosslinkable,oil-resistant,and bio-based elastomer from fumarate

Poly(diethyl fumarate-co-methoxyethyl acrylate-co-vinyl chloroacetate)(PDEFMV),a novel bio-based elastomer with a saturated structure,was synthesized via redox emulsion polymerization.The glass-transition temperatures of PDEFMV,adjusted through the variation of the diethyl fumarate-to-methoxyethyl acrylate feeding ratio,ranged from-36.1 to-14.8 ℃.The number-average molecular weights of PDEFMV ranged from 384,000 to 46,000 g/mol.In designing the molecular structure,vinyl chloroacetate was used to provide active sites for subsequent vulcanization and crosslinking.The active chlorine groups within the PDEFMV chain reacted with the crosslinking agent trithiocyanuric acid under high temperature and pressure to form a nonsulfur crosslinked three-dimensional network structure.To achieve the desired properties,carbon black(CB,N330) was incorporated to reinforce PDEFMV,leading to the formation of PDEFMV/CB composites.A comprehensive study was conducted on the high-temperature oil resistance of PDEFMV/CB composites.Following immersion in IRM903 oil at temperatures of 150 and 200 ℃ for 72 h,the mass and volume changes in PDEFMV/CB were lower than those observed in commercially available acrylate rubber(AR)/CB,indicating that PDEFMV exhibited superior oil resistance.Furthermore,the aging characteristics and mechanisms of oil resistance in the PDEFMV/CB and AR/CB composites were investigated at different temperatures(150,200,and 250 ℃).The results provide insights into the operational temperature ranges suitable for PDEFMV/CB and offer valuable guidance for potential industrial applications.

Synthesis and evaluation of bio-based elastomer based on diethyl itaconate for oil-resistance applications

Bio-based elastomer poly(diethyl itaconate-co-isoprene)(PDEII) was designed and synthesized by redox-initiated emulsion polymerization from diethyl itaconate and isoprene with mass ratio of 20:80, 40:60, 60:40 and 80:20. The number-average molecular weights of PDEII exceeded 140000 with relatively high yields. The physical properties of PDEII, such as glass transition temperatures and thermostability, were comparable with conventional synthetic elastomers and can be readily tuned by varying the ratio of diethyl itaconate to isoprene. The interaction between silica and PDEII macromolecules was effectively enhanced with the increase of diethyl itaconate content by endowing high polarity. The oil-resistance relevant properties of silica/PDEII80(80% diethyl itaconate, 20% isoprene) such as retention of tensile strength, retention of elongation at break and change in volume even surpass those of silica/NBR 240 S after soaked in ASTM 3# oil at different temperatures.

Design and synthesis by redox polymerization of a bio-based carboxylic elastomer for green tire

Poly(dibutyl itaconate-co-isoprene-co-methacrylic acid)(PDIM) elastomer was designed and synthesized by redox emulsion polymerization under mild conditions. PDIM has high molecular weight, relatively high yield, and low glass transition temperature(Tg). The structure of PDIM was determined by FTIR and NMR, and the carboxyl content was obtained by titration in a non-proton solvent. Tensile strength and elongation at break increased with increasing carboxyl content. In addition, the interaction between PDIM and silica was elucidated by rubber process analyzer(RPA) and TEM, and the results showed that the silica-PDIM interaction was strong, but the silica-silica interaction was weak.

Current trends in bio-based elastomer materials

Elastomers play an irreplaceable role in our society due to their unique properties.Natural rubber is directly obtained from plants and is widely used in tires,shoes,etc.Recently,modified natural rubbers are proposed to expand the application of natural rubber.However,these natural rubbers have a limited variety of molecular structures and may not be able to meet ever-demanding applications.Traditional synthetic elastomers have a variety of molecular structures and their properties are used in various fields,but mainly originate from fossil resources.This review deals with bio-based elastomers,and more specifically natural rubber and bio-based synthetic elastomers.Based on reprocessability,bio-based elastomers can also be divided into bio-based chemically cross-linked ones and thermoplastic ones.Compared to traditional fossil-based elastomers,bio-based ones may alleviate environmental pollution and promote the sustainable development of the elastomer industry.

生物基弹性体的研究进展

石油基合成弹性体发展迅速但存在不可持续的问题,且日益受到节能减排的压力;天然橡胶受环境和气候影响较大,产量有限,我国天然橡胶自给不足,严重依赖进口。面对上述挑战,以太阳能为源头,开发不依赖于化石资源的新一代生物基弹性体是解决橡胶资源短缺的有效手段,也是保障全球橡胶资源安全、长久、稳定供应的必由之路。本文综述两类生物基弹性体的最新研究进展。目前主要有两种思路制备生物基弹性体,一种是利用生物基单体(如乙烯、异戊二烯、衣康酸)通过传统的合成工艺制备生物基异戊橡胶、生物基三元乙丙橡胶、生物基衣康酸酯弹性体等生物基合成弹性体,其性能可与传统非生物基工程弹性体相媲美,有望直接替代现有工程弹性体;另一种是提取植物体自然生成的弹性体如天然橡胶、杜仲胶、蒲公英橡胶等。在双碳战略背景下,随着微生物发酵技术和基因工程技术的迅速发展,生物基弹性体的成本会逐渐接近传统橡胶,其具有广阔的发展前景。

Topological network design toward high-performance vegetable oil-based elastomers

As a kind of bio-derived feedstock,vegetable oil(VO)shows great potential to replace petroleum-based monomers to develop sustainable polymer materials because of its easy availability,low cost,bio-renewable,and environmentally friendly nature.However,due to the high cross-linking density and amorphous nature,directly cured VOs generally tend to be brittle and weak.To date,it is still difficult to adopt VOs and their derivatives as structural materials to prepare high-performance elastomers.To address this important issue,amulti-scale topology design strategy was proposed in this work.First,topology regulation and functionalization of VO-based networks were realized by managing functional groups proportion during the bulk polymerization of epoxidized soybean oil with dimer fatty acids.Furthermore,a second polymer(SN)network was introduced into the VO-based network as a protective layer via interfacial cross-links.The generated VO-based elastomers(VOEs)exhibit unprecedented comprehensive properties(VO content≥70 wt.%,T_(g)as low as−24.4℃,toughness up to 6.8 MJ/m^(3)).Besides,the VOEs also exhibit excellent reprocessability and self-healing capability.Overall,this work developed a novel kind of VOEs with significant comprehensive advantages and provided important inspiration for the preparation of high-performance elastomers throughmulti-scale topology regulation.

Synthesis and properties of phosphorus-containing bio-based epoxy resin from itaconic acid

A phosphorus-containing bio-based epoxy resin(EADI)was synthesized from itaconic acid(IA)and 9,10-dihydro-9-oxa-10-phosphaphenanthrene 10-oxide(DOPO).As a matrix,its cured epoxy network with methyl hexahydrophthalic anhydride(MHHPA)as the curing agent showed comparable glass-transition temperature and mechanical properties to diglycidyl ether in a bisphenol A(DGEBA)system as well as good flame retardancy with UL94 V-0 grade during a vertical burning test.As a reactive flame retardant,its flame-resistant effect on DGEBA/MHHPA system as well as its influence on the curing behavior and the thermal and mechanical properties of the modified epoxy resin were investigated.Results showed that after the introduction of EADI,not only were the flame retardancy determined by vertical burning test,LOI measurement,and thermogravimetric analysis significantly improved,but also the curing reactivity,glass transition temperature(T g),initial degradation temperature for 5%weight loss(T d(5%)),and flexural modulus of the cured system improved as well.EADI has great potential to be used as a green flame retardant in epoxy resin systems.