FTIR与13C NMR研究丁戊共聚物的微观结构及序列分布

采用傅立叶变换红外光谱(FTIR)分析了丁戊共聚物的微观结构,发现采用磷酸酯钕体系得到的丁戊共聚物组成不同,其聚丁二烯链节的顺式-1,4含量为93.1％～97.7％,聚异戊二烯链节的顺式-1,4含量为97.0％～ 97.5％.采用差示扫描量热仪(DSC)测试了丁戊共聚物的玻璃化转变温度,发现丁戊共聚物具有良好的耐低温性能,其玻璃化转变温度随着异戊二烯含量的增加而提高,稍偏离Fox方程,经修正得到的公式为Tg=1.03TgIWI+TgBWB.采用Kelen-Tudos法计算得到丁二烯和异戊二烯的竞聚率分别为1.21和0.73,二者乘积接近于1,表明丁戊共聚物为无规结构.利用碳核磁谱(13C NMR)对丁戊共聚物进行分析,对其二元序列进行了归属,计算得到丁戊共聚物的二元序列浓度以及聚丁二烯链节和聚异戊二烯链节的数均序列长度;采用Bernoullian模型和Markov模型验证了丁戊共聚物的序列分布,发现其序列分布更符合Markov模型,表明磷酸酯钕体系催化丁戊共聚合时,活性链有末端效应.     

PVC／PE交联共混体系的动态力学研究

在ＰＶＣ／ＰＥ共混体系中加入交联剂和引发剂能产生ＰＶＣ－ＣＯ－ＰＥ共聚物，这种共聚物在共混物中可起到增容剂的作用。通过动态力学分析和扫描电镜研究了ＰＶＣ／ＰＥ交联共混体系的相容性。发现引发剂、交联剂、稳定剂和增塑剂等对共混物中的交联反应均有较大的影响。     

PVC／PE交联共混体系的动态学力学研究

在ＰＶＣ／ＰＥ共混体系中加入交联剂和引发剂能产生ＰＶＣ－ＣＯ－ＰＥ共聚物，这种共聚物在共混物中可起到增容剂的作用，通过动态力学分析和扫描电镜研究了ＰＶＣ／ＰＥ交联混体系的相容性，发现引发剂，交联剂，稳定剂和增塑剂等对共混和的中的交联反应均有较大的影响。     

SAN共聚物组成对PVC/ABS共混物相容性的影响

采用乳液聚合技术通过改变共聚单体的投料比(St/AN)合成了一系列不同AN结合量的ABS接枝共聚物粉料和SAN共聚物.将其与聚氯乙烯(PVC)和邻苯二甲酸二辛酯(DOP)熔融共混分别制得了PVC/ABS、PVC/SAN、PVC/ABS/DOP和PVC/SAN/DOP共混物,利用SEM、TEM和动态力学粘弹谱仪(DMA)对共混物的相容性和相结构进行了表征.结果发现,在PVC/ABS共混体系中,尽管改变接枝SAN共聚物的AN结合量,PVC和SAN共聚物均为不相容体系;在该共混物中引入增塑剂DOP后,虽然当SAN共聚物AN结合量小于23.4 wt%时,共混物在室温以上只存在一个tanδ峰,但形态结构研究结果表明共混物仍为不相容体系,共混物的相区尺寸明显地依赖于SAN共聚物中的AN结合量,当AN结合量为23.4 wt%时相区尺寸最小.     

SIS/石油树脂共混体系的阻尼性质

通过动态力学性能分析研究了嵌段共聚物聚苯乙烯-异戊二烯-苯乙烯（SIS）／油树脂共混体系的阻尼性质。SIS的硬段聚苯乙烯含量越高，损耗因子（tanδ）峰值温度和粘流温度越高。含有脂肪族系（C5系）石油树脂共混体系的粘流温度比含有氢化芳香族系（C9系）的高。石油树脂的软化点提高，tanδ峰值温度上升。随着石油树脂的含量增大，tanδ峰值增大，并向高温移动，但储能模量（E＇）却先大幅度减小，而后缓慢增大。石油树脂和SIS的软段聚异戊二烯（PI）具有更好的相容性。SIS／N油树脂共混体系的阻尼性能优异，如SIS-A／E120（100／125）在-11～115℃范围内tanδ〉0．3。     

聚四氢呋喃/聚苯乙烯交联嵌段及接枝共聚物的合成与阻尼性能

合成接枝共聚物和嵌段共聚物是研究阻尼材料的重要途径,这是由于可以在较广的范围内,调整共聚物的结构,使之具有良好的阻尼性能。这里我们选择了端羟基聚四氢呋喃与顺丁烯二酸酐反应,制成端乙烯基大分子单体及端乙烯基遥爪低聚物。然后与苯乙烯共聚,制成接枝共聚物和嵌段共聚物。从两者的比较中探讨各种因素对共聚物阻尼性能的影响规律。认为研究结果将有益于阻尼材料的分子设计,在反应体系及合成方法上,都比较简便,适于工业生产,便于推广应用。     

胆甾液晶／聚合物多组分体系的结构与性质研究——Ⅰ.胆甾醇壬酸酯…

应用ＤＳＣ、偏光显微镜和动态力学分析，研究了胆甾液晶与甲基丙烯酸甲酯－甲基丙烯酸丁酯无规共聚物共混体系的相容性及相态转变，表明共聚物的组成、分子量大小可抑制胆甾液晶的相态转变，给出了形成稳定相容的液晶／高分子体系的最佳条件。     

聚二甲基硅氧烷/聚氨酯共混体系的增容作用(Ⅰ)

采用二甲基硅氧烷-b-乙二醇嵌段共聚物(DMS-b-OE)对聚二甲基硅氧烷/聚氨酯(PDMS/PU)共混体系的增容,重点研究了增容共混体系的微观形态结构和力学性能之间的关系。扫描电子显微镜、动态力学分析和力学性能测试结果表明:DMS-b-OE对PDMS/PU具有优良的增容作用,改善了PDMS/PU共混体系的相容性,提高了该共混物的力学性能。其抗张强度由3.4MPa提高到7.6MPa。     

端羟基液体聚丁二烯和聚甲基丙烯酸甲酯多嵌段共聚物的表征

本文研究了一种交联的多嵌段丁羟和聚甲基丙烯酸甲酯共聚物的动态力学性质、热膨胀系数。计算了热力学参数。其交联点间分子量约为945。其特征阻尼行为表明这种共聚物是半相容的多嵌段共聚物,它具有优异的力学阻尼。     

胆甾液晶／聚合物多组分体系的结构与性质研究──I．胆甾醇壬酸酯／聚（甲基丙烯酸甲酯－甲基丙烯酸丁酯）混合体系的相变行为

应用ＤＳＣ、偏光显微镜和动态力学分析，研究了胆甾液晶与甲基丙烯酸甲酯－甲基丙烯酸丁酯无规共聚物共混体系的相容性及相态转变．表明共聚物的组成、分子量大小可抑制胆甾液晶的相态转变．给出了形成稳定相容的液晶／高分子体系的最佳条件．     

高分子力学阻尼材料的研究——Ⅰ.填料对氯化丁基橡胶的力学阻尼行为的影响

本文研究了填料对氯化丁基橡胶在玻璃化转变温度以上的温度范围里的力学阻尼行为的影响。在T_g-36℃的范围里,通过测定填料表面吸附的结合橡胶和填料的表面积,用填料-橡胶界面积函数和单位重量橡胶在填料表面占据的表面积等参数,研究了填料-橡胶相互作用对氯化丁基橡胶的力学阻尼行为的影响;用界面积函数和填充胶中填料的体积份数之积研究填料-填料相互摩擦对它的力学阻尼行为的影响。发现在填料浓度低时,氯化丁基橡胶的力学阻尼行为主要受填料-橡胶相互作用的影响,高浓度时,填料-填料相互摩擦显著地改善了它的力学阻尼行为。     

氯化丁基橡胶/聚(甲基)丙烯酸酯共混物阻尼性能研究

制备了一系列氯化丁基橡胶 (CIIR) 聚 (甲基 )丙烯酸酯 (PMAc)共混复合物 .DMA ,DSC对这些共混物的研究表明 ,无论是共交联体系还是非共交联体系 ,CIIR PMAc共混物均能将CIIR有效阻尼功能区移向高温 ;FTIR分析及抽提实验证明了前一体系CIIR PMAc共混物中共交联结构的存在 ;TEM研究发现 ,共交联改变了CIIR PMAc共混物的微观形貌 .研究结果表明 ,不同组成和结构的PMAc的引入 ,导致共混物中CIIR的Tll转变和Tg 转变受到不同程度的抑制 ,因此引起由共交联体系和非共交联体系制得的CIIR PMAc共混物显示出不同的阻尼行为 .     

SYNTHESIS OF POLYACRYLAMIDE WITH PENDANT POLY(BUTYL ACRYLATE) CHAINS USING THE MACROMER TECHNIQUE AND STUDIES ON THEIR PROPERTIES

INTRODUCTIONSince Milkovich and Chiang[1] developed a method of preparing copolymers with uniform side chains by usingthe macromer technique, the synthesis of copolymers with uniform side chains from different macromers hasbeen studied extensively. Milkovich et al. reported the synthesis of polystyrene macromer through termination ofliving polystyrene anions with methacryloyl chloride and its copolymerization with butyl acrylate to formthermoplastic elastomer[2]. Rempp[3] obtained polyoxy…     

磺化丁基橡胶离聚体及其共混物的动态力学性质

<正> 含10％摩尔以下的离子且主链为柔性的离聚体是一种热塑性弹性体。在动态力学性质方面呈现特殊的行为,表现在贮能模量(1gE′)与温度的关系中有橡胶态平台出现。最早Otocka等指出,(丁二烯-甲基丙烯酸)共聚物无橡胶态平台,经金属离子中和后产生橡胶态平台,且E′增加。Agarwal,Makowski等则报道磺化乙丙胶离聚体的橡胶态平台随离子含量提高而加宽,随硬脂酸锌的加入而缩短。Fitzgerald及Weisst结合X-射线小角散射研究了甘油及邻苯二甲酸二辛酯对磺化聚苯乙烯离聚体的动态力学性质的影响。     

Exploring the effect of radiation crosslinking on the physico‐mechanical,dynamic mechanical and dielectric properties of EOC–PDMS blends for cable insulation applications

This work focuses on the effect of electron beam irradiation on the physico‐mechanical, dynamic mechanical and dielectric properties of blends based on ethylene octene copolymer (EOC) and poly dimethyl siloxane (PDMS) rubber. It is found that electron beam irradiation caused considerable improvement in the physico‐mechanical properties; the tensile strength was enhanced by nearly 35% for 70:30 EOC:PDMS blend. Phase morphology of the blends analyzed before irradiation by scanning electron microscopy (SEM) exhibited droplet/matrix morphology with sizes of the PDMS rubber domain varying from 0.55 µm to 0.47 µm as the amount of PDMS rubber decreased from 30 wt% to 10 wt%. This reduction in the PDMS rubber domain has been correlated with the physico‐mechanical properties of the blends. Further, the dynamic mechanical properties and creep behavior of these EOC:PDMS blends before and after irradiation has been studied. It is inferred that the 70:30 blend after radiation crosslinking shows a 17% decrease in the creep compliance, i.e. higher creep resistance compared to neat blends. All the radiation crosslinked blends exhibited lower dielectric constant, lower dielectric loss and higher electrical resistivity as compared to the virgin blends which makes it suitable for cable insulating application. Copyright © 2016 John Wiley & Sons, Ltd.     

Preparation of high damping elastomer with broad temperature and frequency ranges based on ternary rubber blends

Based on the blends of chlorinated butyl rubber (CIIR), nitrile butadiene rubber (NBR) and chloroprene rubber (CR), a kind of high damping elastomer with broad temperature and frequency ranges is prepared. CIIR/NBR binary blend is prepared to take advantage of the immiscibility and the large difference in cross‐link density of the different phases caused by the curatives and accelerators migration. The dynamic mechanical analysis reveals that the binary blend was immiscible and its loss factor (tanδ) versus temperature curves show two separated and expanded loss peaks when compared with those of pure cured CIIR and NBR. In order to improve its damping properties at room temperature, the third component CR with the polarity between CIIR and NBR was blended into the binary blend. The resulted CIIR/NBR/CR ternary blend has gained effective damping properties (tanδ > 0.3) in the temperature range of ?86.4 to 74.6°C and the frequency range of 10^?2 to more than 10⁹ Hz. Other effects on the damping properties of the ternary rubber were also studied. Copyright © 2013 John Wiley & Sons, Ltd.     

在烃类溶剂中制备丁基橡胶的研究

<正> 关于多分散性对丁基橡胶加工行为的影响,有人进行了研究,近年来人们对丁基橡胶的分子量分布与加工性能的研究,又有新的报道,结果表明,丁基橡胶的分子量分布对其加工时收缩变形有很大的影响,我们曾用过渡金属卤化物和卤代烷基铝-加氢汽油催化体系合成了丁基橡胶,但在加工时收缩率大和不均匀,我们利用高聚物沉淀分级原理,在烷烃溶剂中添加氯代烃(CH_2Cl_2,CH_3Cl),混合溶剂制备的丁基橡胶,其分子量分布及加工收缩性能比单用汽油溶剂时有显著改进,其综合性能基本上达到了Polvsar 301水平。     

EPR-g-PS热塑弹性体的形态结构

电子显微镜观察表明,以乙丙橡胶(EPR)为主干,聚苯乙烯(PS)为支链的接枝共聚物EPR-g-PS的基本形态是高度分散的聚苯乙烯微区(约几百?)存在于乙丙橡胶连续相中的两相体系,随接枝共聚物中聚苯乙烯含量增加,微区形态发生变化,少量的接枝共聚物在PS与EPR共混物中起“增容剂”作用,使分散相微区变得小而均匀,多重玻璃化转变的存在进一步证实了接枝共聚物相分离的形态结构。     

Interfacially modified LDPE/GTR composites with non-polar elastomers: From microstructure to macro-behavior

This paper provides some new insights into the mechanism of interaction and modifications in thermoplastic composites based on low density polyethylene (LDPE), ground tire rubber (GTR) and non-polar elastomer. The composites were prepared using a co-rotating twin-screw extruder at variable LDPE/GTR ratio and constant elastomer content. Two types of commercial elastomer were applied: styrene-butadiene-styrene (SBS) block copolymers (Kraton^®) with different topologies (linear/branched) and partially cross-linked butyl rubbers (Kalar^®) with different Mooney viscosities. Processing characteristics, static mechanical properties (tensile strength, elongation at break, hardness), dynamic mechanical properties, thermal properties and morphology of the resulting thermoplastic composites were investigated. Microstructure analysis shows that modification of LDPE/GTR composites with non-polar elastomers caused encapsulation of GTR particles within the elastomer phase. This phenomenon has significant influence on macro-behavior of thermoplastic composites based on LDPE/GTR blends. The results indicate that SBS copolymer improves interfacial interactions between GTR and LDPE, which enhances mechanical and thermal properties of the composites. On the other hand, cross-linked butyl rubber showed partial compatibility with LDPE and low compatibility with GTR particles.