氯醚橡胶的现状和拓展

介绍了氯醚橡胶的现状(生产厂家、类型、牌号、单体组成及特性)以及氯醚橡胶的拓展情况,其中包括4种无铅无ETU(亚乙基硫脲)环保硫化体系(三嗪、噻二唑、双酚和喹喔啉体系)。介绍了氯醚橡胶在低渗透燃油胶管、生物柴油燃油胶管和减振橡胶制品(特别是空气弹簧)中的应用情况。     

二元共聚氯醚橡胶硫化体系的对比试验

进行两种无铅无促进剂ETU硫化体系[三嗪硫化体系(硫化剂TCY/促进剂DPG/碳酸钙/氧化镁硫化体系)和喹喔啉硫化体系(硫化剂XL-21S/促进剂P-152/氢氧化钙/氧化镁硫化体系)]与有害的亚乙基硫脲硫化体系(促进剂ETU/四氧化三铅和促进剂ETU/氧化镁硫化体系)对二元共聚氯醚橡胶(ECO)性能影响的对比试验。结果表明:喹喔啉硫化体系胶料硫化速度快、交联程度高、物理性能良好,但抗焦烧性能差,喹喔啉硫化体系可作为ECO的无铅无促进剂ETU的环保硫化体系替代传统促进剂ETU/四氧化三铅硫化体系;三嗪硫化体系胶料硫化速度适中、抗焦烧性能和交联效果较好,硫化特性和物理性能与传统促进剂ETU/氧化镁硫化体系胶料相近,但必须解决非环保促进剂DPG的替代问题。     

氯醚橡胶加工技术(3)

第3章配方技术氯醚橡胶一般是利用其侧链氯甲基的反应热进行硫化的。在硫化速度方面。均聚氯醚橡胶和共聚氯橡胶差异不大，共聚氯醚橡胶稍快些；在硫化度方面，均聚氯醚橡胶略高于共聚氯醚橡胶。氯醚橡胶使用的硫化剂，最初是用Hercules公司发表的多胺化合物，尔后采用该公司发表的由通式R［（OA）xNH。」r表示的化合物和咪哩。但是，用这些化合物硫化时胶料焦烧快．难以得到适宜的硫化速度．而且存在硫化胶耐热老化性差的问题。因此不适用。继之开发了胶／硫黄、含硫化合物并用硫化体系。该硫化体系通过活性剂的选择可容易地控制硫化速…     

低压缩永久变形氯丁橡胶的配方研究

探索了改进氯丁橡胶(CR)压缩永久变形的硫化体系。在用氧化锌,氧化镁为硫化体系的基本配方中,使用由三甲基硫脲(TMU)与邻苯二酚硼酸二邻甲苯胍盐(PR)组成的TMU/PR硫化体系,能获得低压缩永久变形体硫化胶。但是,这种硫化体系,会使混炼胶的存放稳定性下降,存放中引起早期自硫。为了克服这种缺点,就PR的机能进行了研究,发现邻苯二酚和硼酸的酯(CTOB)是PR的先驱物质,并清楚地了解到并用的TMU/CTOB硫化体系与TMU/PE硫化体系一样,同样获得低压缩永久变形的硫化胶,而且CR混炼胶的存放稳定性也好。     

汽车用胶管的技术进展

介绍汽车用胶管的技术进展。汽车用胶管是品种多、使用材料广的复合结构橡胶制品，胶层主体材料主要为NBR、CR、EPDM、氢化丁腈橡胶、氯醚橡胶、氯化聚乙烯橡胶、卤化丁基橡胶、氯磺化聚乙烯橡胶、氟橡胶和硅橡胶等，增强材料主要为聚酯、锦纶和芳纶等。橡塑和全塑燃油软管的应用已较广泛。空调胶管多设置聚酰胺防渗层。125℃级散热器胶管胶料采用EPDM／硫黄硫化体系配合，150℃级散热器胶管胶料采用EPDM／过氧化物硫化体系配合。我国散热器胶管（主要为125℃级产品）已多用针织法生产。制动胶管最好采用用过氧化物硫化、少用或不用软化剂的EPDM内层胶。为适应无铅化要求，胶管胶料要采用无铅配合剂和用包塑硫化工艺替代包铅硫化工艺。     

不同硫化体系天然橡胶胶料的动态性能研究

采用橡胶加工分析仪分析不同硫化体系对天然橡胶(NR)胶料动态性能的影响。结果表明:随着频率增大,混炼胶和硫化胶的储能模量(G')均增大,而混炼胶的损耗因子(tanδ)减小,硫化胶的tanδ增大;随着应变增大,混炼胶和硫化胶的G'均减小,而混炼胶的tanδ在应变大于20%时迅速增大,硫化胶的tanδ在应变为2%时出现峰值;随着温度升高,混炼胶的G'减小、tanδ增大,而硫化胶的G'增大、tanδ减小;不同硫化体系的硫化胶在3种扫描状态下,G'从大到小的顺序为半有效硫化体系、平衡硫化体系、普通硫化体系和有效硫化体系,单硫键、双硫键与多硫键保持一定的比例可获得较高的G'。     

不同硫化体系对氟橡胶/氯醚橡胶共混物性能的影响

在固定氟橡胶(FKM)硫化体系(双酚AF)的条件下,研究了改变氯醚橡胶(CO)硫化体系对FKM/CO共混物硫化特性以及硫化胶的物理机械性能、耐老化性能、耐油性能及热稳定性的影响。结果表明,采用促进剂NA-22/MgO体系时,FKM/CO共混物具有较好的硫化特性,硫化胶的综合物理机械性能较好,但耐老化性能仍需改善;采用促进剂TCY/MgO/CaCO3体系时需要较长的硫化时间,且焦烧性能较差;并用促进剂TMTD或促进剂DTDM后混炼胶的交联效果变差;FKM/CO共混物具有较好的热稳定性且热失重起始温度高于300℃。     

不同硫化体系对环保型硬丁腈橡胶性能的影响

以松香酸皂与油酸皂组成的复合乳化体系制备的中试产品丁腈橡胶(NBR)为基胶,分别用硫黄体系和过氧化物体系进行硫化,研究了NBR混炼胶的硫化特性和硫化胶的物理机械性能、耐老化性能、耐油及耐寒性能,并与传统产品NBR 3604进行了比较。结果表明,采用硫黄体系时,NBR混炼胶的硫化程度较浅,硫化速率较慢;采用过氧化物体系时,NBR混炼胶的硫化程度较深,硫化速率较快,NBR胶料宜采用过氧化物硫化体系进行硫化;2种硫化体系下制得NBR硫化胶的物理机械性能与NBR3604硫化胶相差不大,过氧化物硫化体系制得NBR硫化胶的耐老化性能较好;与NBR 3604硫化胶相比,2种硫化体系下制得NBR硫化胶的耐寒性稍好,耐油性稍差。     

提高氯醚三聚物胶料老化性能的活化体系

环氧氯丙烷三聚物的一个独特特征是其含有双硫化点，即环氧氯丙烷（ECH）单体上的氯和烯丙基缩水甘油醚（AGE）单体上的双键，见示意图1。氯硫化点可以采用Zeon化学公司的无铅硫化体系硫化，如Zisnet（TCY）或乙烯基硫脲（ETU）。AGE单体上的不饱和基团可以用传统的硫化体系（硫黄或过氧化物）硫化。     

RPA分析天然橡胶不同硫化体系的动态性能

用RPA分析不同硫化体系对NR动态性能的影响进行研究。研究发现：频率增加,混炼胶和硫化胶的G’增加,混炼胶的Tanδ减小,硫化胶的Tanδ增加;应变增加,混炼胶和硫化胶的G’减小,混炼胶的Tanδ在应变大于20%迅速增加,硫化胶的Tanδ在应变2%出现峰值;温度增加,混炼胶的G’减小、Tanδ增加,硫化胶的G’增加、Tanδ减小。不同硫化体系三种扫描下,硫化胶的G’顺序：SEV>EC>CV>EV,主要是单硫键、双硫键与多硫键保持一定的比例才能获得较高的G’。     

热塑性苯酚甲醛树脂的分子量、游离苯酚含量对胶料加工性能的影响

树脂补强体系下的橡胶硫化实际上是树脂网络和橡胶网络的形成以及相互穿插的过程,热塑性苯酚甲醛树脂的分子量以及游离酚含量势必会对树脂网络的形成产生影响,从而影响橡胶的硫化以及胶料的加工过程。本文就是制备出不同分子量的热塑性苯酚甲醛树脂以及不同游离酚含量的热塑性苯酚甲醛树脂,测试含有这些树脂胶料的加工性能,得出结论,并且用这些结论分析市售的热塑性苯酚甲醛树脂对胶料加工性能的影响。     

冷缩电缆附件用高温硫化硅橡胶的制备与研究

研究乙烯基生胶的种类,气相白碳黑,结构控制剂的种类和用量;耐漏电起痕添加剂,无卤阻燃剂的用量,以及硫化体系等对冷缩(预扩张)电缆附件用硅橡胶的物理力学和电性能的影响。结果完全满足冷缩电缆附件的特殊要求。另发现铂金加成硫化更适合冷缩电缆附件的生产与加工。     

烃类选择氧化过程中自由基的调控策略与工业氧化应用研究进展

催化烃类氧化是提供合成树脂、合成纤维和合成橡胶等大宗化学品以及各类精细化学品的基本工艺,在化学工业中具有重要的地位。目前工业上的烃类氧化工艺普遍需要高温高压条件,苛刻条件可以使氧气活化及碳氢键断裂产生自由基。本文从均相催化、非均相催化、仿生催化等方面对近年来催化氧化反应的研究进展进行了回顾,梳理了催化氧化中的自由基机理。总结了仿生催化体系中自由基稳定性和定向性调控机制等方面的研究现状,提出了高效催化剂的设计、自由基的传递及调控机制等方面将是催化氧化领域的重要研究方向。     

Catalytic Processes for Biomass-Derived Platform Molecules Valorisation

Nowadays, biomass is an interesting raw material for chemical industry, and the valorisation of its derivatives becomes in a sustainable alternative against to the depletion of fossil sources necessary for the production of energy, fuels and chemicals. Different organic compounds, such as sugars, polyols, furanics, as well as several acids (i.e. levulinic acid, succinic acid, itaconic acid, 3-hydroxy-propionic acid, among others) can be obtained after a primary treatment of the lignocellulosic-type biomass. These bio-derived molecules can be used as “platform chemicals” for the synthesis of numerous chemical products (i.e. components and additives for fuels, solvents and paintings, new monomers for polymer industry, etc.). In this review, the possibilities of valorisation via novel catalytic processes of some of the most promising biomass(cellulose/hemicellulose)-derived intermediates and platform chemicals for obtaining both conventional and new high added-value chemicals for industry will be assessed, also including cascade-type (or “one-pot”) catalytic processes recently developed.

     

共聚氯醚橡胶的再生及再生胶硫化体系的配合

研究了机械法再生硫化共聚氯醚橡胶（ECO）薄通次数及辊距对其性能的影响以及ECO再生胶的硫化体系的配合，结果表明通过适当机械再生工艺制造的ECO再生胶是可行的。较好的再生工艺条件为辊距0．4mm和薄通20次。ECO再生胶较好硫化体系配合为：NA-220．4；四氧化三铅4；硫黄0．2。     

Efficient metal‐free aerobic oxidation of aromatic hydrocarbons utilizing aryl‐tetrahalogenated N‐hydroxyphthalimides and 1,4‐diamino‐2,3‐dichloroanthraquinone

BACKGROUND: Hydrocarbon oxidation reactions are central to numerous processes that convert bulk chemicals into useful and higher‐value products. In this investigation, an efficient metal‐free catalytic system for aerobic oxidation of aromatic hydrocarbons was successfully established by synthesizing a series of aryl‐tetrahalogenated N‐hydroxyphthalimides and applying these compounds with 1,4‐diamino‐2,3‐dichloroanthraquinone (DADCAQ). RESULTS: Ethylbenzene was oxidized with 82.3% conversion and 86.9% selectivity to acetophenone catalyzed by the system of TCNHPI/DADCAQ under 0.3 MPa of molecular oxygen at 100 °C for 5 h. Other hydrocarbons were oxidized with high efficiency using this catalytic system. For example, indane can be converted completely to indan‐1‐one with 98.0% selectivity. CONCLUSION: A highly efficient metal‐free catalytic system consisting of TCNHPI and DADCAQ was developed for the oxidation of aromatic hydrocarbons with molecular oxygen. Aryl‐halogen substituents served to significantly increase the activities of the catalytic system. The results in this study can form the basis for the design of an efficient hydrocarbon oxidation process. Copyright © 2008 Society of Chemical Industry     

Biodegradation of chlorophenols using the cell‐free culture broth of Phanerochaete chrysosporium immobilized in polyurethane foam

A cell‐free culture broth of Phanerochaete chrysosporium immobilized in polyurethane foam has been evaluated for the biodegradation of chlorophenols. Lignin peroxidase, manganese peroxidase, and oxalate concentrations in cell‐free culture broth were measured and compared to find the optimum combination of secondary metabolites for the highest biodegradation of chlorophenols. The isozyme distributions and their expression levels were significantly different and changed with increases in the culture time. The oxalate concentration was also found to vary, depending on culture time. Cell‐free broth containing an optimal combination of secondary metabolites showed the greatest biodegradation of 2,4,5‐chlorophenol in the presence of veratryl alcohol and H₂O₂. Phenols with greater numbers of chlorines were degraded more efficiently by this cell‐free culture broth according to the results of biodegradation experiments for five chlorophenols, including 2‐, 4‐, 2,4‐, 2,4,5‐, and pentachlorophenol, as well as phenol. This degradation efficiency correlated well with remaining lignin peroxidase activity during degradation. Cell‐free culture broths may readily be used for biodegradation of highly recalcitrant chemicals since the system would not be affected by the toxicity of the chemicals nor would the adsorption characteristics of the cells be of concern. © 2002 Society of Chemical Industry     

羧基丁腈橡胶的硫化性能

用无硫硫化体系、低硫高促进剂硫化体系、普通硫黄硫化体系、过氧化物硫化体系、金属氧化物硫化体系和硫黄／金属氧化物硫化体系对羧基丁腈橡胶（XNBR）进行了硫化,研究了XNBR的硫化性能、物理机械性能、耐老化性能、压缩永久变形和耐油性能。结果表明,采用普通硫黄硫化体系、硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的综合物理机械性能较好;用无硫硫化体系、低硫高促进剂硫化体系和硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐老化性能较好;用硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐磨性、压缩永久变形较好;用普通硫黄硫化体系和硫黄／金属氧化物硫化体系所得到的XNBR硫化胶的耐油性能较好。     

Novel bismuth ferrite‐based lead‐free ceramics with high energy and power density

In this work, a new lead‐free relaxor ferroelectric 0.60BiFeO₃‐0.34BaTiO₃‐0.06Sr(Al_0.5Nb_0.5)O₃ (BBFTO‐SAN) ceramic was prepared via the conventional solid‐state reaction method. High recoverable energy density (1.75 J/cm³) and efficiency (81%) were achieved, which is superior to some other lead‐free ceramics. Good thermal stability in a wide temperature range (30‐120°C) was also investigated in this system. Moreover, we first studied the charge‐discharge performance of bulk BFO‐based energy storage ceramics and obtained an ultra‐high power density p_D (~57 MW/cm³) as well as a large current density value of ~1353 A/cm². Consequently, all the results indicate that this ceramic is a promising lead‐free candidate for energy storage materials.     

Defect free coatings from two-pack isocyanate curable acrylic dispersions

The combination of isocyanate crosslinking groups and water as continuous phase in coatings provides a real challenge to the coatings industry. Especially the ability of the crosslinker to react with water and liberate carbon dioxide is a problem. CO₂ will be entrapped in the film, resulting in poor aesthetic properties and porous films with reduced resistance properties. In this paper it will be shown that the choice of acid monomer and the acid value have a significant effect on the physical drying rate of the films’ on the level of water remaining in the film after cure, and on the rate of decrease of the NCO concentration and CO₂ blister formation. Increasing the acid value will result in faster NCO loss and more CO₂. The same effects are reached when acrylic acid is chosen over methacrylic acid, which in turn yields a faster NCO concentration decrease and more CO₂ blisters than βCEA. A faster decrease of the NCO group concentration does not necessarily lead to a faster tack free time. By careful selection of the type of acid defect free films without CO₂ blisters can be formed with a thickness of at least 300 μm (dry). CO₂ blister formation is caused by the presence of water soluble poly-acid which remains in the film enabling the reaction of the isocyanate group with water.