橡胶-金属硫化粘合体180°剥离行为的研究

本文通过建立“过渡区”剥离破坏模型,利用分子链断裂理论,对橡胶-金属硫化粘合体的180°剥离行为进行了研究。并利用不同流化体系的橡胶与金属的粘合体的剥离行为差异很大的结果进行了验证。     

N—339炭黑填充天然橡胶与金属硫化粘接复合体剥离特性的研究

对金属－橡胶硫化粘接复合体的剥离行为进行了研究，考察了Ｎ－３３９炭黑填充量对同一粘接试样双向１８０°剥离行为的影响，结果表明：对２０～４０ｐｈｒ炭黑填充量的天然橡胶而言，同一粘的试样的双向１８０°剥离行为体现出各向同性，而当Ｎ－３３９填充量为６０ｐｈｒ时，同一粘接试样的１８０剥离表现为明显的各向异性，本文对这一有趣的实验现象进行了探讨，在前报的基础上提出了部分新见解。     

浅谈氟橡胶硫化用促进剂

氟橡胶以其优异的性能被广泛应用于航空、航天、汽车、石油开采与加工、化工、仪表、机械工业及医药卫生等部门，成为现代科技发展必不可少的原料。塑性橡胶为了转化成所需优异性能的弹性橡胶或硬橡胶，就必须经过硫化。硫化过程对弹性体的性质有决定性影响。在硫化过程中只要在橡胶中加入少于1％的硫化促进剂，不仅能几十的加硫化速度，大大提高硫化设备的生产量，而且也影响着所得硫化胶的性能。这是由于硫化促进剂在硫化反应中参于和促进了自由基的生成。这些自由基与橡胶分子链（聚合物基团）的不同链段相互作用，在短时间内使有线性的－－有规立构的或分枝的聚合物转变成无规的三维结构。所生成的交联键有不同的特性，随键的类型而变，与所用的有促进剂的结构密切相关。这些交联键的生成使含氟硫化胶在一定程度上获得了新的综合物理力学性能。     

离子交联聚合物──一类新型塑料及热塑性橡胶

离子交联聚合物──一类新型塑料及热塑性橡胶潘少波，谢洪泉（湖北工学院化学工程系，４３００６４）ｌ引言离子交联聚合物，简称为离聚体，是一类既有重要科学意义又有明显商业价值的聚合物。所谓离子交联聚合物就是分子链上连接有一定量无机盐基的聚合物。一般定义为含...     

金属有机涂层与丙烯酸酯橡胶的直接硫化粘合

文中介绍了丙烯酸酯橡胶(ACM)与铁、镍或不锈钢(SUS304)等金属材料在硫化时直接粘合的新技术，通过6—烯丙基胺—1．3．5—三嗪—2．4—二硫醇单钠(DAN)的电化学聚合在金属表面形成聚合物薄膜，然后直接与丙烯酸酯橡胶进行硫化粘合。为了与历来的金属电镀相区别，上述对金属表面的改性也称之谓聚合物电镀，聚合物薄膜的厚度会明显影响聚合物电镀金属与丙烯酸酯橡胶粘接的剥离强度。即薄膜厚度在25nm以内，剥离强度随厚度的变化急剧增大，且在超出这一厚度值时仍能保持足够高的剥离强度，呈现出完全是橡胶表面层的内聚破坏。粘接件的剥离强度虽会因硫化剂用量的增加而残小，但在正常的配合剂用量下仍呈现出橡胶表面层内聚破坏。橡胶的硫化温度和硫化时间对粘接件的剥离强度的影响不大。用该方法制得的粘接件具有优异的耐老化和耐油性能。     

硫化状态

硫化状态（state of cure）也被称作硫化程度，是指胶料在特定的温度和时间条件下，橡胶大分子之间所达到的交联程度。凡已添加了硫化体系的橡胶，始终处于进行状态的硫化过程之中。无论从技术或工艺的角度，我们都希望能抓住最理想的硫化状态（正硫化）。如果低于这个理想状态，意味着欠硫，各项性能因未达到充分交联而偏低；反之，如果超越了理想交联状态（即过硫），则会导致过度交联，某些性能又会从最高点下降，这意味着硫化错过了最佳时机。在天然橡胶硫化中，橡胶分子的断链超过了交联，     

粒度与聚合物-填充剂偶联对粒子补强聚合物粘弹性玻璃转化的效应

解析用填充剂粒子补强的多种交联聚合物的粘弹玻璃─橡胶的软化转变过程。研究发现,与链段松弛运动过程相对应的损耗模量峰值(玻璃转化)并未受炭黑填充聚丁二烯中粒子比表面积或受到从苯乙烯丁二烯共聚物到二氧化硅的硅烷化学偶联的大幅影响。使用这些材料,损耗角正切(tanδ)中的峰值与温度之间关系所形成的形状和量值存在巨大差异,但这是由于受到填充剂网络堵塞的影响,在橡胶态中小应变存储模量所发生的变化。用简单的松弛模型来显示在填充剂橡胶中粘弹玻璃转化的这种特点,不必用关于在填充剂表面附近流动性受限的聚合物层的概念来解释粘弹结果。用带超尖钨针尖的原子力显微镜,显示出在填充剂粒子附近的弹性体有一些变硬,但它并没有对这些材料中链段的力学特性产生明显影响。     

丁腈橡胶耐热配方的优选研究

１．前言橡胶在高温热或热氧作用下,产生两类变化,即物理变化（变软）;化学变化（降解、交联、交联链破坏、氧化等）。无论是在纯粹的热的作用下或热氧作用下,都可引起聚合物主链的裂解和交联网的破坏,或者发生进一步的交联,随之发生橡胶的硬化或脆变。橡胶制品的耐高温性能是指在高温条件下使用时,应该在较长的时间内保持正常的物理机械性能,如弹性、强度、伸长率、硬度等。橡胶在这种情况下性能稳定的本质原因是橡胶分子在高温下能够抵抗氧、臭氧、腐蚀性化学介质、高能辐射及机械疲劳等因素的影响,其分子结构不会发生显著变化和…     

氟橡胶的直接硫化粘接（橡胶与橡胶及橡胶与金属间的粘接）

氟橡胶的直接硫化粘接（橡胶与橡胶及橡胶与金属间的粘接）森邦夫著李书春摘译１．前言就目前而言，氟橡胶的价格较高，因此常将其与廉价橡胶复合或混合，又因其强度低、硬度低，故常用金属等材料予以增强，制造复合橡胶制品。这样，大多数氟橡胶制品都采用氟橡胶与金属或...     

N－339炭黑填充天然橡胶与金属硫化粘接复合体剥离特性的研究

对金属－橡胶硫化粘接复合体的剥离行为进行了研究，考察了Ｎ－３３９炭黑填充量对同一粘接试样双向１８０°剥离行为的影响。结果表明：对２０～４０ｐｈｒ炭黑填充量的天然橡胶而言，同一粘接试样的双向１８０°剥离行为体现出各向同性；而当Ｎ－３３９填充量为６０ｐｈｒ时，同一粘接试样的双向１８０剥离表现为明显的各向异性。本文对这一有趣的实验现象进行了探讨，在前报的基础上提出了部分新见解。     

Crosslinking of ultra-high molecular weight polyethylene in the oriented state with dicumylperoxide

Dicumylperoxide was used to crosslink ultra-high molecular weight polyethylene in the oriented state. Completely gelated fibre-networks with a tenacity up to 1.4 GPa were obtained. Storage at 195°C for 1 h left the tensile properties of the crosslinked filaments at room temperature practically unchanged, and vulcanization avoided fibre fibrillation upon failure. It was concluded that to combine high strength with high gel content, crosslinking should be peformed after the polyethylene chains have attained a high degree of orientation.     

Vulcanization kinetics of nano-silica filled styrene butadiene rubber

It was shown that the physical filler-polymer and filler–filler interactions, apart from the filler surface chemistry, has a substantial role in controlling the vulcanization kinetics of styrene butadiene rubber filled with nano-silica in a sulfur vulcanization system. Kinetic studies by the oscillating disc rheometer, differential scanning calorimeter, and swelling tests revealed that the vulcanization rate goes through a maximum as loading of silica increases, but conversion in crosslinking continuously decreases as the amount of silica increases. The effect of silica loadings on the vulcanization reactions was linked to the immobilization of rubber chains around particles as well as in a polymer-mediated filler network, which were differentiated by the nonlinear viscoelastic behavior of rubber vulcanizates. By surface modification of nano-silica, the accelerating/decelerating effects of nano-silica on the vulcanization reactions were altered corresponding to the non-linear viscoelastic behavior of the vulcanizates. Therefore, a mechanism was proposed which correlates vulcanization kinetics of rubber to the dynamics of chains influenced by the reinforcing fillers.     

Chemically crosslinked high-density polyethylene

Chemical crosslinking of high-density polyethylene was studied. The amount of gel produced by a given peroxide concentration depends on the molecular weight of the polymer. More scission reactions, during the crosslinking process, occur in low-density than in high-density polyethylene crosslinked with Varox and Luperox 130 peroxides. The rheological behavior of partially crosslinked polyethylene is useful and convenient for quality control, for characterization, and for studies on the various mechanisms associated with the crosslinking process.     

Peroxide crosslinking of a styrene‐free unsaturated polyester

Thermoset unsaturated polyesters are usually obtained by the crosslinking of unsaturated polyester chains dissolved in an unsaturated, reactive, monomeric diluent, which is usually styrene. This article describes a new approach in which styrene‐free unsaturated polyester chains are intrinsically cured into a crosslinked matrix. The gel time, gel content, swelling degree, glass‐transition temperature, dynamic mechanical properties, tensile properties, and molecular weight between crosslinks (calculated according to both the Flory–Rehner equation and the theory of rubber elasticity) of the crosslinked polymer are studied as a function of the peroxide concentration. All properties change considerably upon the addition of small amounts of peroxide (between 1 and 2 wt %) and change to a lesser extent with higher peroxide concentrations (up to 6 wt %). The thermal properties of the isolated gel fraction are studied as a function of the peroxide concentration. The sol fraction demonstrates a plasticizing effect on the crosslinked network, affecting the glass‐transition temperature and stress–strain behavior of the crosslinked polymer. In light of the crosslink densities derived from swelling experiments, a molecular structure and crosslinking mechanism are suggested for the gel fractions of 1 and 6 wt % peroxide crosslinked unsaturated polyester chains. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

溴化丁基橡胶的热可逆共价交联

利用季铵化反应的热可逆特性,采用含有叔胺官能团的聚合物替代传统交联剂,研究了溴化丁基橡胶(BIIR)的交联反应活性及交联的热可逆性.结果表明,硫化温度和硫化时间对交联BIIR的凝胶含量有显著影响,在160 ℃×30 min的硫化条件下,交联剂呈现出较高的交联活性;不同温度下的转矩测定和190 ℃二次热压的塑性流动证实交联BIIR具备热塑加工性.     

交联型特辛基酚醛树脂酚羟基间位的溴化改性

以交联型特辛基酚醛树脂为原料进行改性,得到了一种交联型酚羟基间位溴化特辛基酚醛树脂,采用红外光谱（FTIR）、核磁碳谱（NMR）对树脂的结构进行了表征,结果表明成功地在酚羟基的间位上取代上了溴。采用莫尔法滴定反应测定剩余溴含量,计算得到苯环上的溴化率为84.7%。采用凝胶渗透色谱（GPC）对改性前后的酚醛树脂进行表征,结果表明经过溴化改性的酚醛树脂的数均分子量、重均分子量有所降低,分子量分布变窄。根据交联型特辛基酚醛树脂的交联机理,分别对交联型特辛基酚醛树脂、交联型链端溴化特辛基酚醛树脂树脂和交联型酚羟基间位溴化特辛基酚醛树脂交联橡胶的硫化历程和物理力学性能进行测试,结果表明改性后的酚羟基间位溴化特辛基酚醛树脂交联橡胶的硫化程度、硫化速度、力学性能都有明显提升。     

Elastic Behaviour of Ternary Rubber-filled Vulcanizates

Near-equilibrium stress–strain measurements have been carried out on ternary rubber vulcanizates. The effect of variation of the butyl rubber content on the elastic behaviour of the ternary rubber vulcanizates has been studied. It has been found that butyl rubber (IIR) is less sensitive to the vulcanization system used than either natural rubber (NR) or styrene–butadiene rubber (SBR). One can obtain a partially crosslinked system with an IIR phase embedded in the crosslinked matrix of NR and SBR. The role played by carbon black during mixing of the ternary blend has been investigated. The Mooney–Rivlin relationship was used to describe the behaviour of the ternary rubber matrix. The constants 2C₁ and 2C₂ have been calculated by use of the strain-amplification factor and the total crosslink density of the ternary rubber–carbon black systems has been investigated. The data have been evaluated in terms of the molecular theories of rubber elasticity. The elastic behaviour was found to be intermediate between the affine and phantom limits of the theory. © of SCI.     

TMPTMA在硅橡胶中的应用研究

研究了助交联剂三羟甲基丙烷三甲基丙烯酸酯(TMPTMA)对硅橡胶硫化性能、力学性能、低温性能和粘接性能的影响。结果表明,加入少量TMPTMA能改善硅橡胶的硫化特性和工艺性,提高硫化胶的硬度,降低硅橡胶的结晶温度,并有效提高硅橡胶与金属的粘接强度;但TMPTMA用量超过一定数值后,由于TMPTMA部分自聚合,在硅橡胶内形成一定的交联网络,造成两相界面粘接力变差,致使硅橡胶的拉伸强度降低。当TMPTMA用量为1份时,硅橡胶具有最佳的综合性能。     

Effects of crosslink density and length on the number of intramolecular crosslinks (defects) introduced into a rubbery network

Estimates are presented for the effects of the crosslink density, or the molecular weight of polymer chains between crosslinks, and the length of crosslinks, or crosslinking agents, upon the expected ratio of internal or intramolecular (possibly elastically ineffective) to external or intermolecular (elastically effective) crosslinks introduced in rubber networks crosslinked in both the dry and dissolved states. Model calculations are performed on cis-1,4-polyisoprene with the following results: (i) in rubber networks formed by crosslinking in the dry state, the number of possibly inactive, intramolecular crosslinks introduced is negligibly small; and (ii) the relative number of intramolecular crosslinks introduced may become appreciable for those networks formed by lightly crosslinking low molecular weight rubber molecules in solutions, where the volume fraction of rubber present is small, using initiators that produce short crosslinks.     

Mass transfer characteristics of natural rubber/ethylene vinyl acetate blends

The transport behavior of natural rubber/ethylene vinyl acetate (NR/EVA) blends has been investigated using aromatic hydrocarbons as probe molecules, in the temperature range of 26–56°C. It has been observed that the solvent uptake decreases with increase in the EVA content of the blends. The blends were crosslinked by three systems, viz. sulfur, dicumyl peroxide (DCP), and a mixture consisting of sulfur and peroxide. The DCP crosslinked system exhibited the lowest solvent uptake. The differences in the transport behavior of the blends, crosslinked by different modes, has been described in terms of the nature of crosslinks introduced between the macromolecular chains during vulcanization. The mechanism of transport has been found to deviate from the regular Fickian behavior, observed with conventional rubbers, with an increase in EVA in the blends. The dependence of the transport coefficients on blend composition, crosslinking systems, nature of penetrants, and temperature was studied. The blend–solvent interaction parameter, enthalpy, and entropy of sorption have also been estimated from the transport data. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2691–2702, 2003