高岭土填充橡胶共混物的性能及表征

以一种高岭土为增强相,分别填充天然橡胶、丁苯橡胶、顺丁橡胶、丁腈橡胶、三元乙丙橡胶、氯丁橡胶和硅橡胶,制备高岭土/橡胶复合材料,通过力学和热老化性能测试、红外光谱和偏光显微镜测试分析,确定了高岭土在各种橡胶中填充的最佳配比,研究高岭土的用量对橡胶力学性能、热老化性能和相容性上的影响,并与白炭黑填充橡胶进行比较。实验表明,除扯断伸长率外,高岭土/橡胶具有优异的力学和耐热性能,高岭土与橡胶有较好的相容性,且适合刚性橡胶的补强。     

环保型丁腈橡胶与同系列通用牌号产品的性能比较

对比了环保型丁腈橡胶N 41 E和3308 E与同系列的非环保型丁腈橡胶N 41和3308的门尼黏度、硫化特性、力学性能、耐老化性能及发泡性能。结果表明,丁腈橡胶N 41 E的加工性能优于N 41,发泡性能稍逊于N 41,二者的耐热空气老化性能和硫化特性基本相当;丁腈橡胶3308 E的加工性能和发泡性能优于3308,操作安全性、300%定伸应力、永久变形和耐热空气老化性能则稍逊于3308。     

New silicone rubbers, 2. Biocompatible silicone rubbers

Biokompatible silicone rubbers have been prepared using fillers based on two types of modified amorphous silica: (i) silica containing covalently bonded reactive H-Si-groups ( 1 ) obtained by reaction of silica with methyldichlorosilane, and (ii) silica with covalently immobilized antithrombogenic agent ( 5 ), prepared by reaction of 1 with divinylbenzene, graft copolymerization with acrylic acid and subsequent esterification with amylose sulfuric acid esters ( 2 ) as a heparinoid. Silicone rubbers (SR's) were obtained by hydrosilation curing of commercially available silicone components using 1 or 5 as fillers. In contrast to 5, 1 is incorporated covalently into the silicone network. Both SR types exhibited good mechanical properties as well as excellent tissue compatibility: contrary to SR's filled with nonmodified silica the cell growth of endothelian cells on the SR's with modified fillers was found to be almost identical to that on cell culture plates.     

New silicone rubbers, 1. Hydrophilic silicone rubbers

3-O-Allylglucose ( 1 ), allylglucoside ( 2 ) and sucrose-allylether-mixtures ( 3 ), respectively, protected by trimethylsilyl (TMS)-groups have been used as unsaturated components in crosslinking of commercially available RTV silicone components. The resulting hydrophobic silicone rubbers were converted into hydrophilic types with covalently bonded sugar residues by hydrolysis to split off the TMS-groups. Silicone rubbers with glucose residues exhibited equilibrium water contents (EWC) from 2 to 9% dependent on the molar ratio of 1 and 2 , respectively, to the Si-vinyl component. The mixtures 3 can be used as crosslinking agent without additional Si-vinyl component to give EWC's of more than 30%.     

Properties of thin films of isotactic polypropylene blended with polyisobutylene and ethylene-propylene-diene terpolymer rubbers

An experimental study was carried out to investigate the kinetic, morphological and thermodynamic properties of thin films of isotactic polypropylene (iPP) blended with several elastomers such as ethylene-propylene-diene terpolymer (EPDM) and three samples of polyisobutylene (PIB) with different molecular masses. The addition of the rubber to iPP causes drastic modifications in the morphology, nucleation density, spherulite growth rate and thermal behaviour of iPP. Such modifications depend strongly on the chemical and molecular mass of the added elastomer and on the composition of the blend. All the elastomers studied seem to act as nucleating agents for the iPP spherulites. The addition of PIB to iPP results in a reduction of the spherulite growth rate G, whereas the addition of EPDM does not seem to have a great influence. For the iPP/PIB_HM iPP/PIB_MM and iPP/EPDM blends a depression of the equilibrium melting temperature T_m, with respect to that of pure iPP, is observed. This depression is increased for the blend containing 20% rubber. This effect is probably related to phenomena of partial miscibility in the melt and to the coexistence of processes such as molecular fractionation and preferential dissolution of the more defective molecules.     

通用橡胶

主要介绍了通用橡胶,尤其是通用合成橡胶的现状及今后的发展趋势。     

T300/QY9512复合材料的耐湿热性能

介绍了QY9512双马树脂的特性及其在RFI复合材料成型工艺中的应用，测定了树脂的流变曲线，对T300／QY9512复合材料的耐湿热性能从Tg和力学性能两个方面进行了研究。试验结果证明T300／QY9512复合材料在150℃、干态和湿态下，力学性能保持率较高，耐湿热性能好。     

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.     

新型白炭黑改性橡胶研究

采用2种新型白炭黑替代常用白炭黑来改性天然橡胶（NR）、顺丁橡胶（BR）、丁笨橡胶（SBR）、三元乙丙橡胶（EPDM）、丙烯酸酯橡胶（ACM）和硅橡胶。研究不同用量和不同种类的白炭黑对上述几种橡胶进行改性,通过对硬度、扯断伸长率、拉伸强度、磨耗和耐老化性能的测试,确定白炭黑的最佳用量和最适宜的种类。结果表明：白炭黑填料用量为80份时效果最好,普通白炭黑适合做EPDM的补强剂,碱法白炭黑对NR、SBR和ACM的改性效果更好,而酸法白炭黑改性的橡胶拉伸强度和硬度很小,不适于补强;白炭黑对硅橡胶的改性效果不好,得到的产品硬度很小,无法进行力学性能测试。     

Dynamic-mechanical properties of polybutadiene rubbers

The dynamic properties of high-cis (98%) and cis-trans (42% cis) polybutadienes, crosslinked with 0.1 to 1.0% of crosslinking agent, have been studied using a torsion pendulum method over the temperature range ?170 to +20°C. For the high-cis rubber plots of damping factor (tan δ) against temperature showed the expected peak in the glass-transition region with an additional peak in the neighbourhood of 0°C attributable to crystallization. The cis-trans rubber showed two damping maxima in the transition region, separated by 30 to 40°C (depending on the degree of crosslinking), suggesting incipient phase separation of the component structures. The rebound resilience of the high-cis rubber at room temperature exceeded that of the cis-trans, reaching 92% at the highest crosslink density. Plots of resilience versus temperature for both rubbers showed a single minimum in the glass transition region.     

Properties of thermally conductive silicone rubbers filled with admicellar polymerized polypyrrole-coated Al2O3 particles

Polypyrrole (PPy) nanolayers were introduced on the surface of alumina (Al₂O₃) particles via admicellar polymerization. The properties of silicone rubbers (SRs) filled with PPy-coated Al₂O₃ and pristine Al₂O₃ as thermally conductive fillers were studied and compared. The results demonstrate that the addition of PPy-coated Al₂O₃ leads to a better interfacial compatibility but lower cross-linking density of the composites than pristine Al₂O₃. The improvement in the compatibility and the decrease in the cross-linking density are paradoxes in affecting mechanical properties. The improvement in the compatibility shows a slight predominance on the strength at low-filler contents. Lower cross-linking density of modified-Al₂O₃/SR composites led to a better processing performance and a higher maximum filler loading amount than the pristine Al₂O₃/SR composites, which is beneficial to increasing the thermal conductivity and maintaining a relatively good strength. The PPy-coated Al₂O₃/SR composite with 83 wt% filler content has a thermal conductivity of 1.98 W/(m K) and a tensile strength of 2.9 MPa, and the elongation at break was 63%. Functionalized fillers by admicellar polymerization used in the fabrication of filler/SR composites not only improve the interfacial compatibility but also optimize and expand the functions of the composites, which has great significance for the production and application of thermally conductive SR in some branches of industry (automotive, electrical engineering, etc.) in the future.     

Orientation-strain behaviour of crosslinked rubbers

Procedures for the evaluation of quantitative orientation parameters using wide-angle x-ray scattering data are outlined. Data are presented for crosslinked natural rubber. a copolymer of polyethylene and polyvinylacetate and for polymethylmethacrylate. These quantitative orientation data are compared to the predictions of models of rubber elasticity. Critical comparisons are made with affine and phantom chain models and the variable network constraint model recently introduced by Erman and Flory. The effects of entanglements and segmental interactions are also considered. An approach is introduced which allows the evaluation of the level of intersegmental interaction contribution to the orientation-strain behaviour.     

H300碳纤维及其预浸料性能研究

对H300碳纤维性能进行了测试,结果表明H300碳纤维与T300碳纤维力学性能基本相当。试验了3238A/H300碳纤维热熔预浸料制造工艺,制造出合格预浸料。测试了3238A/H300碳纤维复合材料物理力学性能,结果表明3238A/H300碳纤维复合材料满足要求。     

Microbiological deterioration of rubbers and plastics

The effects of micro-organisms on rubbers and plastics are reviewed, with reference to the chemical nature of the polymers and their possible additives. The confused and sometimes contradictory nature of the evidence is indicated, and it is concluded that both synthetic and naturally-occurring polymers are attacked but it is not possible at this stage to say which chemical groups in each polymer are susceptible.     

Properties of some cast polyurethane rubbers prepared from poly-ε-caprolactone polyols and diisocyanates

Polyurethanes were prepared by a one-step method from poly-ε-caprolactone (PCL) diols, diisocyanates, and a triol crosslinking agent (either PCL triol or trimethylolpropane). The influence of composition on mechanical properties was examined. In some formulations the elastomeric properties were lost by crystallization of the PCL segments. The occurrence and rate of crystallization were influenced by the composition and factors such as hydrolytic degradation and oil swelling. In one series of polymers the susceptibility to crystallization could be predicted from the composition. These materials showed melting and glass transitions when examined by differential scanning calorimetry and thermomechanical analysis. The molecular weight of the PCL diol had a greater influence on the glass transition temperature than the diol concentration.     

高性能系列氟橡胶

介绍了几种不同性能的氟橡胶混炼胶：低压缩永久变形氟橡胶FX－4、FX－5／FX－6，可用于制造在空气、石油基润滑油、燃油、液压油和双酯类合成润滑油中工作的海域中固定密封件；改善低温性能的氟橡胶FX－13，其脆性温度可达－45℃；低摩擦因数氟橡胶FX－10，可改善胶料的导热性；改善工艺性能的氟橡胶FX－70H，其硫化时间短、温度低，热撕裂性能优异。     

Stress relaxation of anhydrous gelatin rubbers

Anhydrous gelatin–glycerol compositions exhibit rubbery behavior in the temperature region ?40 to +40°C. and in the gelatin weight fraction range 0.1–0.4. These rubbers are capable of sustaining considerable stress over several decades of time at room temperature or below but flow rapidly in the region 45–60°C. Stress relaxation moduli at 25°C. appear to be insensitive to the substitution of glycerol with water but shear viscosity data indicate that gelatin–glycerol rubbers flow at temperatures about 15°C. higher than their aqueous counterparts.     

用作光致抗蚀剂的环化橡胶

介绍了环化聚异戊二烯和环化聚丁二烯橡胶的研究发展状况、合成方法、结构表征及在光刻胶中的应用,提出了环化橡胶的发展趋势。环化反应是按阳离子型机理进行的;分子结构由含不饱和双键的线形高分子链转变成含特殊多环结构的线形高子分链;由单体直接生产环化橡胶是研究的发展方向。