SMC／BMC的增韧研究进展

汽车等应用领域对ＳＭＣ／ＢＭＣ的冲击韧性提出了更高的要求，本文详细介绍了ＳＭＣ／ＢＭＣ低收缩添加剂（ＬＰＡ）的增韧功效，并着重介绍采用含活性端基的橡胶增韧ＳＭＣ／ＢＭＣ。     

端胺基液体丁腈橡胶增韧环氧胶黏剂的研究概况

介绍了端胺基液体丁腈橡胶（ATBN）增韧改性环氧胶黏剂的研究概况。由于端胺基液体丁腈橡胶具有活性端胺基,与环氧基在室温下即可进行化学键合,省略了通常的橡胶-树脂预聚合工艺,是一种性能优良的环氧树脂增韧剂。     

端异氰酸酯基聚丁二烯液体橡胶

兰州石油化工公司化工研究院液体橡胶室继推出端羟基聚丁二烯 (ＨＴＰＢ Ｌ)及聚丁二烯 丙烯腈 (ＨＴＢＮ Ｌ)液体橡胶工业试产品后 ,又推出了端异氰酸酯基聚丁二烯 (ＩＴＰＢ)及端异氰酸酯基聚丁二烯 丙烯腈 (ＩＴＢＮ)液体橡胶。据报道 ,ＩＴＰＢ是由ＨＴＰＢ与ＴＤＩ在特定条件下合成。ＩＴＰＢ系列 4种中试产品的技术指标为 :相对分子质量分别为 380 0、30 0 0、2 5 0 0及 2 0 0 0 ,ＮＣＯ含量 0 .6、0 .9、1.2及 1.6ｍｍｏｌ/ｇ ,40℃粘度分别低于 30、2 6、2 0及 15Ｐａ·ｓ。它们可用于环氧树脂增韧、电子灌封胶等。由于ＩＴＰＢ粘度…     

反应性端基聚丁二烯系列液体橡胶在环氧树脂改性增韧方面的应用

综述了含反应性端基聚丁二烯系列液体橡胶（以下简单PBLR）品种、性能及特点，概括比较了PBLR改性增韧环氧树脂方法及特点；分别列举了PBLR改性环氧树脂在微机电浇注料，树脂砂轮，水利机械涂敷，电子灌封及飞机粘合剂等方面的应用。     

聚砜封端反应的研究

用紫外光谱法测定了聚砜树脂封端后前后端基的变化，研究了不同因素对ＰＳＦ封端反应的影响，得到了ＰＳＦ封端反应的适宜条件。     

建筑用甲硅烷基化的聚氨酯

1　前言有机功能硅烷封端聚氨酯 (ＳＰＵＲＳＭ)预聚物用于胶粘剂和密封剂的配方中已有许多年了[1,2 ] 。ＳＰＵＲ技术不仅提供了具有良好的耐久性、优异的粘接性能的含有游离ＮＣＯ基的预聚物[3] ,而且聚合物的模量可高可低 ,以适应不同的应用。用类似于传统聚氨酯化学的方法 ,采用不同种类的多元醇和二异氰酸酯 ,以宽范围的物质的量比 ,可以合成出具有不同内在性能的ＳＰＵＲ预聚物[4 ] 。在这里 ,聚氨酯的软 -硬链段的典型的结构 -性能关系 ,对其性能 ,特别是诸如模量、柔韧性和强度这些物理性能有很大影响。有机功能性硅烷封端剂的加入…     

液体橡胶的研究进展Ⅱ.端基聚丁二烯液体橡胶的合成

概述了端基聚丁二烯液体橡胶的常见种类和特性,主要介绍了端羟基聚丁二烯液体橡胶、端羧基聚丁二烯液体橡胶和端羟羧基聚丁二烯液体橡胶的合成技术,包括自由基乳液聚合法、自由基溶液聚合法、负离子聚合法等.     

聚苯乙烯增韧用橡胶的发展

详细叙述了聚苯乙烯的增韧方法及所用胶种，采用特殊结构的低顺式聚丁二烯橡胶和低粘度、无凝胶的高顺式ＢＲ增韧ＰＳ可制得性能优异，且各种物性的高抗冲ＰＳ。指出，高顺式ＢＲ有可能成为最理想的增韧胶种。     

阻燃耐烧蚀聚氨酯包覆材料的研究

合成了几种类型的以异氰酸基封端的液体预聚物。制备了九种聚氨酯树脂。评价了ＰＵＲ中芳杂环含量及阻燃元含量对产品阻燃性与烧蚀性的贡献。筛选出一种综合较为优良的ＰＵＲ包覆材料。并完成了静止发动机点火实验，效果明显。     

端羧基聚丙烯酸正丁酯改性环氧树脂的结构与性能

<正> 自60年代中期以来,活性液体橡胶改性(增韧)环氧树脂一直是非常活跃和引人注目的研究课题。这个领域的研究工作主要集中于端羧基液体丁二烯—丙烯腈共聚物增韧环氧树脂的研究和应用方面。人们还不断地努力开拓新的液体橡胶改性剂,如聚环氧丙烷、聚己内酯、聚丁二烯,聚氯丁二烯、四氢呋喃共聚醚和聚硅氧烷等。这些液体聚合物都带有羧基、羟基、环氧基、巯基和氨基等能通过固化剂(促进剂)与环氧基和羟基等进行化学反应的官能团。这些官能团可无规地悬挂在聚合物链上,也可是遥爪     

弹性体增韧不饱和聚酯研究

综述了目前液体橡胶、弹性体等增韧不饱和聚酯的研究进展,重点探讨了各类液体橡胶、弹性体增韧UP树脂及相应的增韧机理。发现增韧效果取决于分散相与UP间的相容性及界面间作用力大小,相比较而言,形成互穿网络结构增韧UP树脂因其优异的综合性能是UP增韧未来可能的发展方向。     

Toughening of unsaturated polyester resins with core–shell rubbers

The effects of core–shell rubbers (CSRs) as tougheners on the fracture properties of unsaturated polyester (UP) resins during curing at 110°C are investigated. CSRs were synthesized by two‐stage soapless emulsion polymerizations; the soft core was made from rubbery poly(n‐butyl acrylate), whereas the hard shell was made from methyl methacrylate, ethylene glycol dimethacrylate, and various concentrations of glycidyl methacrylate. Depending on the content of glycidyl methacrylate in the CSR shell and the amount of CSR added to the UP, the fracture properties of the CSR‐toughened UP resins varied. The experimental results are explained by an integrated approach of measurements of the static phase characteristics of a styrene/UP/CSR system, the reaction kinetics, the cured sample morphology, the glass‐transition temperatures, and the fracture toughness with differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, and dynamic mechanical analysis. Finally, the toughening mechanism for the CSR‐toughened UP resins is also explored. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Reactive acrylic liquid rubber with terminal and pendant carboxyl groups as a modifier for epoxy resin

Reactive acrylate rubbers with the terminal and pendent carboxyl groups have been investigated as a modifier for a room temperature curing epoxy resin. The liquid rubbers with varying molecular weights and carboxyl-functionality were synthesized by bulk polymerization of 2-ethyl hexyl acrylate using acrylic acid as a comonomer. The liquid rubbers were characterized by FTIR, ¹³C NMR spectroscopic analysis, nonaqueous titration, vapor pressure osmometry, and solubility characteristics. The liquid rubbers were incorporated into the epoxy resin by the prereact method and the effect of functionality on impact properties of the modified networks were investigated. The results were explained in terms of dynamic mechanical properties and morphology analyzed by scanning electron microscope (SEM). Polym. Eng. Sci. 47:26–33, 2007. © 2006 Society of Plastics Engineers.     

Ionic crosslinking of carboxyl-terminated liquid rubbers with metal oxides

Ionic crosslinking of carboxyl-terminated liquid rubbers with metal oxides and metal carbonates, mainly with the former, were investigated. The liquid rubbers used were a polymer of butadiene (Hycar CTB 2000X162) and a copolymer of butadiene–acrylonitrile (Hycar CTBN 1300X8). The CTBN ionically crosslinked rubbers obtained showed higher tensile strength than the CTB series, due to the polarity effect of the nitrile groups. The ionic rubbers cured with MgO and CaO were studied in detail, and it was found that their tensile strength increased markedly with increase in the metal oxides used, and in addition white carbon and carbon black showed remarkable reinforcing effects. The properties such as tensile strength, elongation, Shore A hardness, and melt index are influenced by humidity. It is characteristic of these ionically crosslinked rubbers that they can be successfully reprocessed.     

Synthesis and characterization of novel room temperature vulcanized (RTV) silicone rubbers using Vinyl-POSS derivatives as cross linking agents

Two kinds of novel POSS cross-linkers were firstly prepared via hydrosilylation of Vinyl-POSS and trimethoxysilane. And two types of novel polydimethylsiloxane (PDMS) polymer composites as RTV silicone rubbers were prepared using Vinyl-POSS derivatives as cross-linkers in the presence of organotin catalyst. To completely exhibit superiorities of two kinds of novel cross-linkers, RTV silicone rubbers prepared with two proportions of different cross-linkers were assessed. The chemical inclusion of novel POSS into PDMS networks by hydrolytic condensation reaction was verified by attenuated total reflection (ATR) infrared spectroscopy. Morphologies, thermal properties, mechanical properties and hardness of these novel RTV silicone rubbers were studied. The results exhibited significantly enhanced effects of POSS on thermal stabilities, mechanical properties and hardness as compared to the PDMS polymers prepared with the traditional tetra-functional TMOS and TEOS cross-linkers. The striking improvements in thermal properties, mechanical properties and hardness could be attributed to the synergistic effect of the increase of dimensionality of cross-linked networks in novel RTV silicone rubbers resulting from special three-dimensional structure of novel POSS cross-linkers, plasticization of self-cross-linked POSS cross-linkers and uniform distribution of POSS cross-linkers.     

Use of acrylate‐based liquid rubbers as toughening agents and adhesive property modifiers of epoxy resin

Carboxyl‐randomized poly(2‐ethyl hexyl acrylate) (CRPEHA) and epoxy‐randomized poly(2‐ethylhexyl acrylate) (ERPEHA) were synthesized by solution polymerization technique in the form of liquid rubbers. The liquid rubbers were characterized by IR and ¹H‐NMR spectroscopic analysis, nonaqueous titration, and GPC. The liquid rubbers were pre‐reacted with the epoxy resin and the modified epoxy networks were made by curing with an ambient temperature curing agent. The modified epoxy networks containing different concentrations of CRPEHA (A‐1) and ERPEHA (B‐1) were evaluated with respect to their thermal and impact properties. The optimum properties were obtained at 10‐phr concentration of a (1 : 1) mixture of CRPEHA and ERPEHA. Fracture surface analysis by scanning electron microcopy indicated the presence of a two‐phase microstructure. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3814–3821, 2004     

Dynamic mechanical,mechanical and morphological properties of reactive thermotropic liquid crystalline polymer/unsaturated polyester/glass fibre hybrid composites

Abstract

Unsaturated polyester (UP) reinforced with self-synthesised reactive thermotropic liquid crystalline polymer (TLCP)–methacryloyl copolymer (LCMC) and glass fibre (GF), the hybrid composites of UP/GF/LCMC were prepared by moulding technology. The dynamic mechanical analysis indicated that storage modulus and glass transition temperature (T _g) of hybrid composites increased significantly because of the addition of LCMC. The effect of LCMC content on the mechanical properties of LCMC/UP/GF hybrid composites such as impact strength, specific strength and modulus and load–displacement relationship were also investigated through static mechanical tests. The mechanical properties of hybrid composites increased significantly because of the addition of LCMC. The crystal behaviour analysis of LCMC/UP blend was investigated by X-ray diffraction and polarising optical microscopy. The results showed that the crystal phase and texture structure of LCMC still existed in the blends after blending with UP. The morphology of fracture surfaces of hybrid composites containing different TLCP contents was observed by scanning electron microscopy. The present paper discussed the mechanism for the improvement of dynamic mechanical and mechanical properties.     

Review on rubbers in medicine: natural,silicone and polyurethane rubbers

Abstract

Natural, silicone and polyurethane rubbers are considered as three important biomaterials which have found widespread applications in medical technology. Biocompatibility, biodurability, sterilisability, processibility, as well as mechanical properties, such as flexibility and resilience, are properties that make these kinds of rubbers appropriate candidates for medical applications. Medical devices based on natural rubber, silicone and polyurethane rubbers include cardiac pacemaker leads, mammary prostheses, artificial skin, catheters, denture liners, diaphragms, blood pressure cuff coil, tubes and seals. These types of rubbers are commonly used in controlled drug delivery systems as a carrier for pharmaceutical agents and in the fabrication of other medical devices. These polymers were evaluated for release of hormones (e.g. estradiol and progesterone), metronidazole, nonoxynol-9, etc. In this paper, some recent advances on the development of these polymers in the biomedical field and some reports on the modification and improvement of their properties such as drug release and mechanical properties are reviewed.     

Toughening of epoxy networks using pre-formed core-shell particles or reactive rubbers

The influence of several additives (liquid reactive rubbers or core-shell particles-CSR) is studied on thermal and mechanical properties of an epoxy network based on diglycidyl ether of bisphenol-A (DGEBA) and dicy (DDA). Using high speed stirring, without any solvent, a good dispersion of the CSR is achieved. It is shown that the glass transition temperature (Tg)of the networks decreases when liquid rubbers are added but remains constant with the addition of CSR.It is demonstrated that every kind of particles favors the shear yielding of the networks, and well fit a modified Von Mises criterion.The fracture energies increase with the addition of rubbers, especially for the rubber with the higher acrylonitrile content. The same toughening effect is obtained with CSR if compared to the lower acrylonitrile content of liquid reactive rubbers but without any decrease in Tg of the epoxy network.