热可逆共价交联热塑性弹性体

热可逆共价交联热塑性弹性体焦书科（北京化工大学高分子材料系，１０００２９）热可逆共价交联反应是一类利用环戊二烯（ＣＰＤ）和双环戊二烯（ＤＣＰ）之间的热可逆转化（即Ｄｉｅｌｓ－Ａｌｄｅｒ反应和逆Ｄｉｅｌｓ－Ａｌｄｅｒ反应）、使含活性基团的橡胶转化成含Ｃ...     

红外光谱法测热可逆共价键交联氯醇橡胶的组成

以交联单体双环戊二烯二甲双缩水甘油酯（ＤＧＤＣＡ）的特征峰（１７１２ｃｍ＾－１）和环氧氯丙烷均聚物（ＰＥＣＨ）的特征峰（７５０ｃｍ＾－１）为定量计算的基准峰,测定不同质量比的ＤＧＤＣＡ与ＰＥＣＨ混合物ＩＲ谱图。混合物组成与光密度比值（Ｄ１７１２／Ｄ７５０）关系的回归方程为：（Ｄ１７１２／Ｄ７５０＝０．０２０９＋６．６４ＷＤＧＤＣＷＥＣＨ）,进而建立了通过Ｄ１７１２／Ｄ７５０求取共聚物中ＤＧＤＣＡ结     

热可逆交联含氯聚合物的力学性能研究

合成了含有端环戊二烯基的硫醇盐,将其作为既可以取代聚合物链上氯原子,又可通过环戊二烯的Diels-Alder反应的可逆性作为可以使含氯聚合物室温交联、高温解交联的交联剂。考察了该交联剂用量对含氯聚合物交联程度与力学性能的影响。     

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.     

聚氯乙烯的离子型热可逆交联研究

通过二胺的烷基化反应，制备了不同链长的二叔胺，利用二叔胺与聚氯乙烯(PVC)链上的活性氯形成季铵盐离子键的反应，制备了具有离子型热可逆交联特性的PVC。在研究中发现，对于硬聚氯乙烯(PVC-U)，适当份数的交联剂能够提高材料的杨氏模量、屈服强度、断裂强度和断裂伸长率；应用于软聚氯乙烯(PVC-S)时，断裂强度、断裂伸长率均得到提高，而永久变形量明显降低，并且交联时间的延长对力学性能影响显著。     

热可逆共价交联软聚氯乙烯性能的研究

以自主合成的含有端环戊二烯基(CPD)的巯酯锑作为热稳定剂兼交联剂,应用于软聚氯乙烯中,考察了交联后PVC的热可逆可加工性,研究了交联剂用量对PVC的力学性能、交联程度和稳定性的影响。     

热可逆性共价键交联氯醇橡胶的制备和性质

以环戊二烯基钠（ＣＰＤ－Ｎａ）与氯醇橡胶（ＣＨＲ）反应，制得了含ＣＰＤ侧基和双环戊二烯交联的聚合物。研究了反应物基团配比、反应温度对凝胶化时间和交联聚合物得率的影响。结果表明，随ＣＰＤ－Ｎａ用量的增加和反应温度的升高，ＣＨＲ形成凝胶的时间缩短。测定了交联聚合物的热可逆转化行为，发现交联聚合物在高温下可发生逆Ｄｉｅｌｓ－Ａｌｄｅｒ反应。     

双交联型丙烯酸酯橡胶性能研究

<正>丙烯酸酯橡胶(ACM)是由丙烯酸酯单体(如丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯和丙烯酸-2-乙基己酯等)与功能化单体(丙烯腈、2-氯乙基乙烯基醚、丙烯酸或者马来酸酐等)进行自由基共聚而得到的一类特种橡胶。其主链为饱和碳链,侧基为极性     

热可逆交联软聚氯乙烯(SPVC)的研究

通过二胺的烷基化反应 ,制备不同链长的二叔胺 ,利用二叔胺与聚氯乙烯 (PVC)链上的活性氯可以形成季铵盐离子键的反应 ,形成交联键 ,制备了热可逆交联PVC。研究了交联剂种类和用量对力学性能、交联程度的影响 ,同时探讨了在不同温度、不同反应时间条件下进行交联对试样力学性能的影响     

软聚氯乙烯热可逆交联性的研究

利用Diels-Alder热可逆反应,合成了含有端环戊二烯基(CPD)的硫醇盐,作为具有热可逆性的交联剂,并将其应用于软聚氯乙烯中。研究了交联剂用量、时间及温度对交联程度的影响。采用DTA差热分析对此交联剂的热可逆特性进行了研究,并通过刚果红法和转矩流变仪测试了热可逆共价交联软聚氯乙烯的热稳定性以及加工流动性。     

Dynamic mechanical properties of acrylic rubber blended with phenolic resin

The dynamic mechanical properties of blends of phenolic resin (PF) and acrylic rubber (ACM) were investigated. PF had good compatibility with ACM and played an important role in the damping of the ACM/PF blends. With the increase of PF content and molecular weight, the peak of loss factor (tan δ) of blends shifted to a higher temperature and became much wider, indicating the convenience to adjust the value of tan δ peak and the temperature range. Fourier Transform infrared spectroscopy detected that the intermolecular hydrogen bonding between the PF hydroxyl groups and the ACM carbonyl groups had made a great contribution to the improvement of damping. Compared with the organic small molecule used in our previous study, PF gifted the blends with equivalent damping performance and much better stability and a lower cost for the application of damping materials. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Comparing effects of silanized silica nanofiller on the crosslinking and mechanical properties of natural rubber and synthetic polyisoprene

The effect of the same amount of precipitated silica nanofiller on the curing and mechanical properties of natural rubber and synthetic polyisoprene was investigated. The silica surfaces were pretreated with bis(3-triethoxysilylpropyl) tetrasulfide (TESPT) to chemically bond silica to rubber. The rubbers were primarily cured by using sulfur in TESPT, and the cure was optimized by the addition of accelerator and activator, which helped to form sulfur chemical bonds between the rubber and filler. Different amounts of accelerator and activator were needed to fully crosslink the filled rubbers. The hardness, tensile strength, elongation at break, stored energy density at break, tearing energy, and modulus of the vulcanizates improved substantially by the incorporation of the filler in the rubber. This was due to high level of rubber-filler adhesion and formation of chemical bonds between the rubber and TESPT. Interestingly, natural rubber benefited more from the filler than did synthetic polyisoprene. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effects of a hindered phenol compound on the dynamic mechanical properties of chlorinated polyethylene,acrylic rubber,and their blend

The dynamic mechanical properties of binary hybrids of chlorinated polyethylene (CPE) and acrylic rubber (ACM) with 3,9‐bis{1,1‐dimethyl‐2[β‐(3‐tert‐butyl‐4‐ hydroxy‐5‐methylphenyl)propionyloxy]ethyl}‐2,4,8,10‐tetraoxaspiro[5,5]‐undecane (AO‐80) and their ternary hybrids were investigated. The addition of AO‐80 was successful in tailoring the damping profile. The ACM/AO‐80 hybrids show only one relaxation, which is larger than that of pure ACM, whereas for the CPE/AO‐80 hybrids, one novel relaxation appears above the glass‐transition temperature of CPE. In the case of CPE/AO‐80/ACM, a supramolecular network was formed by a crosslink due to hydrogen bonding. The replacement of a part of CPE by ACM increased the value in the middle of two peaks. The AO‐80 molecule, which is a bifunctional hydrogen‐bonding acceptor, was found to act as a compatibilizer. In addition, in such ternary hybrids, the tan δ value in the middle of the two peaks was found to be proportional to the slope of the E′ curve at an identical temperature. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 2468–2473, 2001     

含氟丙烯酸酯橡胶的合成及性能

以丙烯酸乙酯、丙烯酸丁酯、含氟丙烯酸酯为单体,采用半连续乳液聚合法合成了含氟丙烯酸酯橡胶(ACM),用傅里叶变换红外光谱表征了其微观结构,考察了含氟单体种类及用量对含氟ACM亲水性、玻璃化转变温度及硫化特性的影响,以及交联剂二乙烯基苯(DVB)用量对含氟ACM硫化胶拉伸性能的影响。结果表明,丙烯酸六氟丁酯或丙烯酸十二氟庚酯(简称G 05)的转化率均超过90%;随着含氟单体用量的增加,ACM乳液涂膜的接触角逐渐增大,当加入质量分数为5%的G 05时,涂膜变为疏水性表面;含氟ACM只有1个玻璃化转变温度,且随着含氟单体用量的增加而逐渐下降;含氟ACM的操作安全性高,在硫化初期具有良好的流动性能;当DVB质量分数为3%时,含氟ACM的拉伸强度达到11.2 MPa。     

Thermal aging on mechanical properties and crosslinked network of natural rubber/zinc Dimethacrylate composites

This article dealt with the relationship between mechanical properties and crosslinked networks of natural rubber (NR) reinforced by zinc dimethacrylate (ZDMA) after thermal aging. After thermal aging at the present experimental conditions, the covalent crosslink density showed a decrease all the time, whereas the ionic crosslink density was stable at 80°C but decreased at a higher temperature. The decrease in the total crosslink density after aging indicates the degradation of the crosslinked network. However, an experimental phenomenon observed was that the tensile strength and tear strength increased in a certain degree after aging at 80°C or at a 100°C for a short time. In addition, the thermal stability of the NR/ZDMA composite was evaluated by thermal gravimetric analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

纳米二氧化钛填充橡胶复合材料的分散结构与性能

用粒径为20～40nm的纳米二氧化钛(B—TiO2)填充天然橡胶(NR)和丁腈橡胶(NBR)制备了橡胶复合材料,研究了B—TiO2在橡胶基体中的分散结构、复合材料的力学性能以及抗菌性能,并与德国Degussa公司的催化剂纳米TiO2(D—TiO2)进行了对比。结果表明,B—TiO2在NR和NBR中表现出良好的分散,绝大多数B—TiO2在橡胶中聚集体尺寸小于100nm,特别是在NR中B—TiO2分散颗粒大小与其原生颗粒大小相近,明显优于D—TiO2在NR中的分散;在B—TiO2用量小的情况下,橡胶复合材料的力学性能基本不受B—TiO2的影响。D—TiO2对橡胶复合材料的老化性能也没有影响。橡胶基体中填充B—TiO2后,其抗菌性能明显提高,当用量超过2份(质量)时,其抗菌性能已经达到较高的水平;D—TiO2／NR抗菌效果与B—TiO2／NR的抗菌效果相当,热氧老化不影响橡胶复合材料中TiO2发挥其抗菌特性。     

导电橡胶力学性能和耐高温性能研究

通过研究补强材料白炭黑以及助剂偶联剂对导电橡胶力学性能的影响分析，发现白炭黑和偶联剂的加入均可有效增强导电橡胶的力学性能，且对导电橡胶的导电性影响不大。当白炭黑添加量为15%，偶联剂的添加量为0.7%时，力学性能相对最佳。此外，还研究了导电橡胶的高温环境适应性，发现在高温96 h内，导电橡胶的力学性能以及导电性能可保持相对较佳的状态。     

Effect of carboxyl on vulcanization and mechanical properties of carboxylated acrylic rubber prepared by 60Co‐γ‐ray‐induced polymerization

Acrylic acid carboxylated acrylic rubber (ACM) and itaconic acid carboxylated acrylic rubber were prepared by ⁶⁰Co‐γ‐ray‐induced emulsion copolymerization. The polymers were characterized using FTIR and ¹³C NMR spectroscopies. The acid value was determined with nonaqueous titration method. The molecular weight and the polydispersity index of the polymers were measured using gel permeation chromatography. The influence of the cure‐site (carboxyl) on the vulcanization and mechanical properties of the ACM was researched by means of rheometric study, gel fraction analysis, mechanical property tests, and dynamic mechanical thermal analysis. The results show that the crosslink density of polymers increases with amounts of the carboxyl cure‐site. The itaconic acid carboxylated ACM has better cure characteristics and mechanical properties than the acrylic acid carboxylated ACM has. In addition, the comparison of ACM prepared by ⁶⁰Co‐γ‐ray‐induced polymerization with ACM prepared by chemical‐initiator‐induced polymerization has been investigated. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 5587–5594, 2006     

Morphology and dynamic mechanical properties of natural rubber/nitrile rubber blends containing trans‐polyoctylene rubber as a compatibilizer

The use of trans‐polyoctylene rubber (TOR) as a compatibilizer for blends of natural rubber (NR) and acrylonitrile‐butadiene rubber (NBR) was investigated using atomic force microscopy (AFM) and dynamic mechanical analysis (DMA). The NR/NBR blends containing varying proportions of TOR were prepared in an internal mixer. AFM micrographs of NR/NBR blend at 50/50 (w/w) composition showed heterogeneous phase morphology with NR as a matrix and NBR as a dispersed phase. Inclusion of TOR in the NR/NBR blend altered the phase morphology by reducing the size of the NBR phase. DMA of NR/NBR/TOR showed reduction in tan δ peak height of NBR and an increase in storage modulus E′ in the rubbery region for the NR/NBR blends. A comparison of the E′ obtained from experimental data with that from theoretical models was made to deduce the location of TOR in the blend. Based on the fittings of calculated and experimental values of E′, it was inferred that TOR was incorporated into the NR phase at lower proportion as well as at the interfacial region at higher proportion. The Cole–Cole plot illustrated the compatibilizing effect of TOR. Copyright © 2004 Society of Chemical Industry