聚异丁烯基热塑弹性体设计合成与性能

通过双端羟基聚异丁烯(HO-PIB-OH)与4,4'-二环己基甲烷二异氰酸酯(HMDI)及1,4-丁二醇(BDO)反应,设计合成一系列具有不同聚氨基甲酸丁二酯硬段长度的聚异丁烯基热塑弹性体(PIB-TPE),研究HMDI/PIB摩尔比值对PIB-TPE的聚集态结构、弹性回复、自修复性能、表面亲/疏水性、动态力学性能和拉伸性能的影响.结果表明:在PIB-TPE中,软段是完全饱和结构的PIB柔性链段,聚氨基甲酸丁二酯硬段通过氢键(无序氢键、有序氢键)形成结晶物理交联微区((3.6±0.5)nm),软段与硬段呈现明显的微相分离现象,常温下形成了三维超分子网络结构,高温下发生结晶熔融与氢键解离,超分子网络结构解散,形成黏流态,降低温度又可形成三维超分子网络结构;随着材料储存时间延长,无序氢键逐渐向有序氢键转变,有利于提高材料的拉伸强度和断裂伸长率.结晶熔融与氢键解离温度依赖于PIB-TPE中硬段长度,当HMDI/PIB摩尔比值小于19,硬段结晶熔融峰温度可达119℃以上,提高了PIB-TPE服役温度.PIB-TPE材料具有良好的弹性回复和自修复性能,且其膜表面的亲/疏水性可以通过HMDI/PIB摩尔比值或正己烷蒸汽常温下诱导表面自组装来调节,当HMDI/PIB摩尔比值从6增加至21,PIB-TPE膜表面的水接触角(WCA)由98.7°降低至77.8°,即由疏水性转变为亲水性.此外,PIB-TPE热塑弹性体中的完全饱和柔性PIB软段赋予其优良的减振阻尼性能,其损耗因子(tanδ)大于0.3的温域较宽(?55~25℃),且tanδ最大值(tanδ_max)达到1.05.上述多嵌段聚异丁烯基热塑弹性体在生物医用、减振阻尼、自修复等功能材料领域具有潜在的应用前景.     

生物基弹性体研究进展

出于对节约石油资源、保护环境、发展循环经济等考虑,用可再生的生物资源代替石油化学品生产高分子材料已成为人们研究的热点。弹性体是一类应用领域非常广泛的材料,但是绝大多数的弹性体都是以石油基化学品为原料合成的,因此研究生物基弹性体对节约石油资源及保护环境具有重要意义。本文对目前研究较多的三类生物基弹性体—生物基聚氨酯弹性体、生物基聚酰胺弹性体、生物基聚酯弹性体作了简要的综述。主要介绍了合成生物基弹性体的原料、合成路线以及相关的生物基弹性体的性能比较。     

聚乳酸热塑性弹性体的研究进展

热塑性弹性体(TPE)是一类应用领域非常广泛且极具发展潜力的高分子材料,然而目前TPE品种所选用的原料(包括单体或聚合物)绝大部分都是源于石油基不可再生资源。作为一种极具潜力替代石油基高分子的生物基脂肪族聚酯材料,聚乳酸(PLA)具有原料来源丰富并可再生、生物降解性良好、强度和模量高等优点,因此聚乳酸TPE的研究吸引了国内外学者广泛的关注。本文综述了PLA嵌段共聚物型TPE和PLA基动态硫化热塑性弹性体(TPV)的最近的研究进展,详细阐述了它们的制备路线以及材料的性能,最后指出了当前PLA热塑性弹性体研究中存在的不足。     

生物橡胶的研究进展

2010年中国成为世界第二大经济体,这意味着中国需要更多的橡胶资源以满足其经济的快速发展。橡胶材料可以通过两个来源得到,一个是源自巴西橡胶树的天然橡胶,一个是源自化石资源的合成橡胶。我国的天然橡胶资源非常短缺,而合成橡胶又不可持续发展。因此,利用太阳能发展生物橡胶是中国橡胶工业可持续发展的未来。生物橡胶包含两大类材料,一类是生物基工程弹性(Bio-based engineering elastomer,BEE),它将可再生的生物质资源发酵得到衣康酸等生物基单体,再经化学合成得到的一类新的弹性体,或者将生物质发酵得到的生物基单体如异丁醇等进一步转化为传统单体如异丁烯等,再经过化学合成得到传统的弹性体;第二类是天然橡胶,包括三叶橡胶和第二天然橡胶(Second natural rubber,SNR),例如蒲公英橡胶、银菊橡胶以及我国特有的杜仲橡胶。本文将对生物基工程弹性体和第二天然橡胶进行综述,由于三叶橡胶的研究历史悠久、文献众多,在此不再综述。     

生物基化工与材料产业技术的开发与探索

本文阐述了中国石油化工集团公司(中国石化)在生物基化工与材料领域的探索路径和发展战略,介绍了中国石化近年来在生物基单体、生物基材料与可降解材料等领域开展的创新实践及取得的阶段性成果,主要包括乳酸—聚乳酸、丁二酸/二元醇—生物可降解材料、长链二元酸—生物基尼龙以及生物质芳烃—聚对苯二甲酸乙二酯(PET)等技术领域.提出了建立生物基化工与材料科学技术平台、突破关键技术、发展新兴产业等建议.     

FDCA基聚酯的合成、性能及应用研究进展

生物质资源是一种储量丰富的可再生资源。生物质资源的高效利用不仅具有非常巨大的经济和生态价值,而且对新能源与生物基合成材料的可持续发展战略具有重大意义。由植物纤维素等生物质材料经生物或者简单化学过程处理,可获得丰富的生物基单体2,5-呋喃二甲酸(FDCA)。FDCA可用于生物基聚酯材料的合成。FDCA系列聚酯材料性能优异,可作为由石油基单体对苯二甲酸(PTA)而合成的芳香族聚酯材料(例如PET)的一种潜在的高性能生物可降解替代材料。本文简要说明了生物基单体FDCA的物性及制备方法,并重点阐述了包括聚呋喃二甲酸乙二酯(PEF)与聚呋喃二甲酸丁二酯(PBF)等一系列FDCA基聚酯材料的合成及性质,同时对FDCA基聚酯材料的应用进展进行了简要介绍,最后对FDCA基聚酯生物基合成材料的发展前景作了初步展望。     

电化学葡萄糖传感器

作为电化学生物传感器中最重要的研究内容之一,葡萄糖生物传感器在数十年的发展中取得了巨大进展。本文综述了近年来利用纳米技术设计的新型电化学葡萄糖传感器的主要研究进展,并从纳米材料维度分类进行了讨论。其中,零维纳米材料主要讨论了包括金纳米颗粒、银纳米颗粒以及铜、铂等金属纳米颗粒材料; 一维纳米材料主要讨论了通过模板法制备的金属或金属氧化物纳米线以及单臂或者多壁纳米管材料; 二维纳米材料主要总结了以碳为基础的石墨烯材料和一些片状的金属材料。纳米材料对电化学葡萄糖传感器的影响主要集中在生物相容性、增强检测灵敏度、酶的固定等方面。此外,本文也对电化学葡萄糖传感器的今后发展做了展望。     

环保型汽油清净剂的研制及性能测试

以聚异丁烯基丁二酰亚胺和脲基氨基甲酸酯化合物为复合清净分散剂、多羟基醚类化合物为协同增效剂，研制了环保型汽油清净剂，通过试验确定了各组分的配比。对汽油清净剂进行了性能测试，如模拟试验、铜片腐蚀性能测试和辛烷值测试等。该汽油清净剂对发动机燃油吸入系统有良好的清洗和保洁功能，达到了降低尾气排放和节省燃油的效果。     

生物基聚酯PTT与PDT的发展概况北大核心CSCD

综述了包括生物基原材料1,3-丙二醇以及生物基乙二醇的生产工艺研究进展,介绍了PTT和PDT两种生物基聚酯在国内外的最新发展,包括两种生物基材料的合成路线、工艺条件等。详细介绍了两种材料现有的纺丝技术的改进,并对PTT(对苯二甲酸1,3-丙二醇酯)、PDT(对苯二甲酸多元醇酯)、PET(对苯二甲酸乙二醇酯)三种产品不同性能做出了比较,展望了生物基聚酯未来的工程化产业化的良好前景。     

用异丁烯溴镁制取α-烯烃基硅烷

α-烯烃基硅烷可用α-烯烃基卥代物在四氢呋喃溶液中制成镁试剂,然后再与适当的烷基(苯基)卥代硅烷作用而得。我们合成多种烷基(苯基)异丁烯基硅烷,并确定其物理常数,这些化合物有热稳定性。用这一方法也合成异丁烯基三乙氧基硅烷,它容易水解而生成聚合物。异丁烯基溴化镁和原硅酸乙酯以2∶1的量反应时,未得到二异丁烯基二乙氧基硅烷;因为溶液加热蒸馏时它就很快聚合。     

Recent progress in bio-based elastomers with intrinsic self-healing mechanisms - part I: Natural rubber modifications

This review is focused on recent achievements in bio-based self-healable elastomeric materials with special regard to elastomers made of natural rubber (NR) and its modified forms, including epoxidized natural rubber (ENR), oxidized natural rubber (oNR) or carbonated natural rubber (CNR). Besides natural rubber, also Eucommia ulmoides gum (EUG), which is an isomer of cis-1,4-polyisoprene, is a material of great interest to obtain bio-based self-healable elastomers. The paper attempts to describe the main classification of the most important intrinsic self-repairing mechanisms, including different types of reversible non-covalent interactions (such as hydrogen bonding, ionic interactions, metal–ligand coordination, shape-memory ability), dynamic covalent bonds (for instance Diels-Alder reversible bonds, dynamic sulfur-sulfur bonds, dynamic ester bonds, boronic-ester exchangeable bonds, dynamic imine bonds, silyl ether exchangeable bonds) and their combinations, which are found in self-healing elastomers. Furthermore, examples of NR-based elastomeric materials are provided and the potential applications proposed by researchers are also presented.     

New developments and directions in the area of elastomers and rubberlike elasticity

There are number of important developments in the area of elastomeric polymers, including (i) network chains of controlled stiffness, (ii) model elastomers (including dangling-chain networks), (iii) fluorosiloxane elastomers, (iv) new thermoplastic elastomers, (v) other new elastomers, (v) bimodal network chain-length distributions, (vi) cross linking in solution or in a state of deformation, and (vii) gel collapse. Interesting elastomeric composites include those with (i) in-situ generated ceramic-like particles, (ii) ellipsoidal fillers, (iii) clay-like layered fillers, (iv) polyhedral oligomeric silsesquioxane (POSS) particles, (v) porous fillers, (vi) elastomeric domains modifying ceramics, and (vii) controlled interfaces. New characterization techniques are being developed for elastomers, and there have been new developments in elasticity theory and in elastomer processing. Some examples of societal aspects of relevance are (i) synthesis of elastomers in environmentally-friendly solvents, (ii) biosynthesis, (iii), recyclability, (iv) improved adhesion to tire cords, and (v) better barrier properties in anti-terrorism clothing. Educational topics include curriculum development, and mobile laboratories for elastomer experiments and demonstrations.     

Applications of Inorganic Polymeric Materials,III: Polyphosphazenes

Summary.  Polyphosphazenes form one of the most important and interesting classes of inorganic polymers having a backbone of alternating phosphorus and nitrogen atoms with phosphorus atom bearing two organic side groups. The most important feature of these polymers is the synthesis route which allows the side groups to be changed over a wide range to obtain a broad variety of products with different properties from elastomers to glasses, water soluble to hydrophobic polymers, bioinert to bioactive materials, and electrical insulators to conductors. In this paper, some novel applications of these polymers in biomedical materials and advanced devices are reviewed.     

Applications of Inorganic Polymeric Materials, III: Polyphosphazenes

Polyphosphazenes form one of the most important and interesting classes of inorganic polymers having a backbone of alternating phosphorus and nitrogen atoms with phosphorus atom bearing two organic side groups. The most important feature of these polymers is the synthesis route which allows the side groups to be changed over a wide range to obtain a broad variety of products with different properties from elastomers to glasses, water soluble to hydrophobic polymers, bioinert to bioactive materials, and electrical insulators to conductors. In this paper, some novel applications of these polymers in biomedical materials and advanced devices are reviewed.     

Effect of Soft Segment Molecular Weight and 3-Methyl Side Group on Microstructural Separation in Polyurethane Elastomers

Abstract

The object of this study was to assess the effect of the chain length and of the pendant 3-methyl side group in the soft segment of polyurethane (PU) elastomers. In addition, the effect of annealing-quenching on the degree of microstructural segregation between the hard and soft segments was also investigated. The study employed electron spin resonance (ESR), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). Samples for ESR measurements were spin-labeled with the nitroxide probe, 4-hydroxy-2,2′,6,6′-piperidine-1-oxyl (TEMPOL), by reaction of an isocyanate group with the hydroxyl group of TEMPOL. The nitroxide label is therefore located at a chain end. The PU's were based on 4,4′-diphenylmethane diisocyanate (MDI), poly(oxytetramethylene) glycols (PTMO), and hydroxyl-terminated random copolymers of tetrahydrofuran and 3-methyl-tetrahydrofuran (THF/Me-THF). Purified 1,4-butanediol (BD) was used as a chain extender. The elastomers made from higher molecular weight (MW) soft segments have better phase segregation than their lower MW counterparts. The 3-methyl side groups on the PTMO backbone have some effect on the arrangements of the two domains. ESR analysis indicated that the increase in the MW of THF/Me-THF decreased the degree of mixing between the hard and soft segments. In PU elastomers made from high MW soft segments, the presence of crystallinity was observed from the DSC measurements. The crystallinity of the soft segments was disrupted by the existence of the 3-methyl side groups.     

Synthesis and properties of biodegradable elastomeric epoxy modified polyurethanes based on poly(ε-caprolactone) and poly(ethylene glycol)

Biodegradable polyurethane elastomers with potential for applications in medical implants with tunable degradation rate and physical properties were synthesized from reaction of epoxy terminated polyurethanes (EUP) with 1,6-hexamethylene diamine (HMDA) as curing agent. Poly(ε-caprolactone) (PCL) and poly(ethylene glycol) (PEG) as well as 1,6-hexamethylene diisocyanate (HDI) were used for preparation of isocyanate terminated polyurethanes which were subsequently blocked with glycidol to prepare EUPs. All materials were characterized by conventional methods, and their properties were studied fully. Results showed that elastomers based on PEG exhibit superior degradation rate and inferior mechanical properties in comparison to elastomers based on PCL. Optimum degradation rate and mechanical properties were obtained from elastomers made from mixture of PCL and PEG base EUPs.     

Thermal degradation of some fluorine-containing elastomers

A study was made, using thermogravimetry, of the thermal stability of some of the most recently produced fluorine-containing elastomers. The evolution of hydrogen fluoride (HF) as a function of time and temperature was also monitored by a fluoride ion selective electrode. Wherever possible both gumstock and compounded forms of the elastomers were examined. Experiments were carried out in air at a fixed rate of temperature rise, or isothermally.The most thermally stable material was a fully fluorinated elastomer and the lowest HF yields were given by polyphosphazene elastomers. Formulation plays a critical rôle in the amount of HF evolved.     

PREFACE

正We are delighted to present this special-themed issue of the Chinese Journal of Polymer Science(CJPS) devoted to the recent advances in self-healing polymeric materials. Selfhealing has been recognized as one of the most attractive topics for advanced polymers in the past few years, enabling their reworkability, durability and reliability.     

Threshold fracture energies for elastomers

Fracture energies have been measured for two types of polybutadiene elastomer, crosslinked to various extents and torn under various conditions. Threshold values, ranging from 40 to 80 jm^?2, were observed for samples torn at extremely low rates of tearing, at high temperatures, and in the swollen state. These values were found to be independent of temperature and rate of tearing, and also of the degree of swelling and the nature of the swelling liquid, provided a correction is made for the reduced areal concentration of molecular chains. They decreased somewhat with increased crosslinking, in good agreement with theoretical predictions of Lake and Thomas.⁶ The results for the two elastomers were substantially the same. These observations are strikingly different from those made at normal temperatures and rates of tearing, when large differences in fracture energy were observed between the elastomers, and between samples crosslinked to different extents, due to energy losses from nonequilibrium deformation processes in addition to the energy required for fracture.     

Hydrocarbon polymers—perspectives

Factors underlying the supply of raw materials and the manufacture of petrochemical-based polymers are discussed, with particular emphasis on future trends and energy consumption. Examples are given of development in monomer synthesis, e.g. for isoprene, and of recent advances in the synthesis and properties of hydrocarbon polymers, specifically new elastomers, together with the likely technological and economic impact.