亚胺基吡啶钴催化乙烯齐聚合和原位共聚合

研究了{2-[2-Me-4-OMe-C_6H_3N=C(Me)]_2C_5H_3N}CoCl_2(催化剂1)催化乙烯齐聚合以及它与不同茂金属催化剂Et[Ind]_2ZrCl_2(催化剂2)、Me_2Si[Ind]_2ZrCl_2(催化剂3)和Me_2Si[2-Me-Ind]_2ZrCl_2(催化剂4)复配,以甲基铝氧烷(MAO)为助催化剂催化乙烯原位共聚合。讨论了茂金属催化剂类型和聚合温度的改变使共聚活性发生变化的规律,并对部分产物的性能进行了测试。结果表明：催化剂1与催化剂2复配在40,60,80℃时催化乙烯原位共聚合均出现了正共单体效应,60℃时出现共单体效应的最大活性为6.4 Mg/(mol·h),高于40℃和80℃时的相应值。同时,催化剂1/催化剂2/MAO和催化剂1/催化剂3/MAO体系随着共聚催化剂金属活性中心的夹角减小,出现正共单体效应时最佳配比点的活性下降;而催化剂1/催化剂4/MAO体系出现了负的共单体效应,密度最低可达到0.9209g/ cm~3.所得支化聚乙烯的物理性能取决于α-烯烃的插入率,插入率主要与茂金属催化剂的结构有关。     

乙烯丙烯气相共聚合的研究

研究了乙烯丙烯气相共聚合的反应条件如反应压力、反应温度和共聚单体比例等条件对聚合活性剂共聚物性能的影响,测定了共聚物中的己烷可溶出物的含量,通过差示扫描量热仪测定了共聚物的热性能,通过核磁共振测定了共聚物中的乙烯含量,利用傅里叶红外光谱仪对共聚物的成分进行了分析。结果表明,反应压力、温度和共聚单体比例均对己烷可溶出物含量影响较大;而共聚物的热力学性能受共聚单体比例影响较大,反应压力和反应温度对共聚物热力学性能影响不明显;共聚单体比例对共聚物中乙烯含量影响较大,而反应压力和反应温度对其影响较小;共聚物的己烷可溶出物中的乙烯含量高于己烷不溶物中的乙烯含量。     

工业流化床乙烯共聚合生产过程中牌号切换的最优化研究

A model of grade transition is presented for a commercialized fluidized bed gas-phase polyethylene production process.The quantity of off-specification product and the time of grade transition can be minimized by the optimization of operating variables,such as polymerization temperature,the ratio of hydrogen to ethylene,the ratio of co-monomer to ethylene,feed rate of catalyst,and bed level.A new performance index,the ratio of melt flow(MFR),is included in the objective function,for restraining the sharp adjustment of operation variables and narrowing the distribution of molecular weight of the resion.It is recommended that catalyst feed rate and bed level are decreased in order to reduce the grade transition time and the quantity of off-specification product.This optimization problem is solved by an algorithm of sequential quadratic programming (SQP) in MATLAB. There is considerable difference between the forward transition and reverse transition of grade with regard to the operating variables due to the non-linearity of the system.The grade transition model is extended to a high space time yield(STY)Process with the so-called condensed model operation.In the end,an optimization strategy for multi-product transition is proposed with two-level optimization of the objective function J(x,u) on the the basis of the optimal grade transition model.A sequential transition of six commercial polyethylene grades in illustrated for an optimal multi-product operation.     

乙烯-丙烯-1-丁烯三元共聚合

采用自制的ziegler-Natta催化剂催化乙烯-丙烯-1-丁烯三元共聚合.考察了1-丁烯/丙烯、铝钛比、反应温度和压力等对三元共聚合的影响.结果表明.三元共聚物中支化度约为26门000 C,其中乙基支链为18/1 000 C、丙基支链为8/1 000 C.在聚合温度为60℃、压力为0.8 MPa、乙烯分压百分数为70%、1-丁烯分压百分数为5.7%和丙烯分压百分数为24.3%时,催化活性最高,为10.5 kg/g.当n(Al)/n(Ti)大于100时,催化活性增加趋势变缓.聚合压力超过0.8 MPa时,催化活性变化不大.聚合平行实验结果表明,上述条件稳定,所得三元共聚物的表观密度为0.32g/cm3,拉伸强度为11～12 MPa、断裂伸长率为540%～560%.     

乙烯与共扼二烯烃共聚合的研究进展

乙烯和共扼二烯烃的共聚合的研究不仅具有理论价值而且还有实际意义。乙烯均聚物通常为塑料；共扼二烯烃均聚物通常为弹性体。两者共聚合，性能相互补充，可得到性能优异的共聚物。另外，共聚合又可为聚合机理的探索提供重要依据，我国应及时开展相关研究，拓展研究领域，在研制新材料方面进一步深入工作。     

茂金属乙烯-辛烯共聚物的研究现状和展望

分析茂金属乙烯-辛烯共聚物(POE)的研究现状和发展趋势.当前研究主要包括改性POE直接用作弹性体材料、POE发泡材料、POE增韧其它聚合物以及动态硫化POE/热塑性树脂热塑性弹性体等方面;茂金属POE凭借优异的综合性能,已成为极具发展前景的新型材料.     

乙烯-乙酸乙烯酯共聚物/聚乙烯热塑性硫化胶的形态结构及流变性能

使用双转子密炼技术制备了具有双连续相结构的乙烯-乙酸乙烯酯共聚物(EVA)/聚乙烯(PE)的热塑性聚烯烃(EVA/PE-TPO)和热塑性硫化胶(EVA/PE-TPV)材料,并利用扫描电子显微镜、Han曲线和vGP曲线对二者的相形貌进行了分析和表征。动态流变行为的结果表明,在低频区,EVA含量对EVA/PE-TPO材料体系的储能模量(G′)和复数黏度的影响均大于EVA/PE-TPV体系;在高频区,组成相同的两种体系的G′相近。当两相的组成比例相同时,时温等效原理适用于210℃以下的EVA/PE-TPV体系。修正Palierne模型对双连续相结构EVA/PE-TPV材料的线性黏弹性的拟合程度不高。     

三元乙丙橡胶-聚丙烯共混型热塑性动态硫化橡胶国内研究概况

介绍了共混组分体系、共混工艺方式及其条件、纤维、微粒改性对三元乙丙橡胶-聚丙烯(EPDM-PP)共混型热塑性动态硫化橡胶性能影响等的研究情况。     

超临界二氧化碳发泡三元乙丙橡胶/低密度聚乙烯热塑性弹性体

研究硫化体系和橡塑比对超临界二氧化碳发泡三元乙丙橡胶（EPDM）/低密度聚乙烯（LDPE）热塑性弹性体物理性能和微观结构的影响。结果表明：采用过氧化物硫化体系的热塑性弹性体的综合物理性能优于采用硫黄硫化体系,随着硫化剂用量的增大,拉伸强度和撕裂强度有一个最大值,硬度上升;橡塑比为40/60时,物理性能达到最佳;LDPE相与EPDM相呈现“海-岛”两相微观结构;泡孔大小均匀性较好。     

Comparative study of copolymerization and terpolymerization of ethylene/propylene/diene monomers using metallocene catalyst

(Ind)₂ZrCl₂ catalyst was synthesized and used for copolymerization of ethylene and propylene (EPR) and terpolymerization of ethylene propylene and 5‐ethyldiene‐2‐norbornene (ENB). Methylaluminoxane (MAO) was used as cocatalyst. The activity of the catalyst was higher in copolymerization of ethylene and propylene (EPR) rather than in terpolymerization of ethylene, propylene and diene monomers. The effects of [Al] : [Zr] molar ratio, polymerization temperature, pressure ratio of ethylene/propylene and the ENB concentration on the terpolymerization behavior were studied. The highest productivity of the catalyst was obtained at 60°C, [Al] : [Zr] molar ratios of 750 : 1 and 500 : 1 for copolymerization and terpolymerization, respectively. Increasing the molar ratio of [Al] : [Zr] up to 500 : 1 increased the ethylene and ENB contents of the terpolymers, while beyond this ratio the productivity of the catalyst dropped, leading to lower ethylene and ENB contents. Terpolymerization was carried out batchwise at temperatures from 40 to 70°C. Rate time profiles of the polymerization were a decay type for both copolymerization and terpolymerization. Glass transition temperatures (T_g) of the obtained terpolymers were between ?64 and ?52°C. Glass transition temperatures of both copolymers and terpolymers were decreased with increased ethylene content of the polymers. Dynamic mechanical and rheological properties of the obtained polymers were studied. A compounded EPDM showed good thermal stability with time. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Improved compatibility of PET/HDPE blend by using GMA grafted thermoplastic elastomer

ABSTRACT

Herein, graft-modified ethylene-1-octene copolymer (POE-g-GMA) and styrene-butadiene-styrene triblock copolymer (SBS-g-GMA) were found to be excellent reactive compatibilizers for immiscible poly(ethylene terephthalate) (PET)/high-density polyethylene (HDPE) blends via in-situ reaction compatibilization. With increase in compatibilizer amount, uniform phase morphology was observed in all the blends. Thus, exhibiting enhanced mechanical properties, especially, the notched Izod impact strength. In comparison with SBS-g-GMA, compatibilizer POE-g-GMA demonstrated greater impact on the compatibility. The addition of 15% POE-g-GMA produced blends with best mechanical properties. Besides, both POE-g-GMA and SBS-g-GMA enhanced the melt viscosity of PET/HDPE blends.     

废橡胶粉/高密度聚乙烯共混物的界面相容性

研究了用改性剂和界面相容剂来强化废橡胶粉与高密度聚乙烯之间界面结合的效果。对废橡胶粉/高密度聚乙烯共混物的热力学性能、动态力学性能及微观结构形态等的研究结果表明,界面相容剂和改性剂的加入增强了共混物的界面相容性,提高了共混物的物理机械性能。     

NBR／HDPE热塑弹性体的形态与性能

用动态硫化方法制备也ＮＢＲ／ＨＤＰＥ共混型热塑弹性体,电子显微镜研究其形态表明,尽管ＮＢＲ的用量超过了ＨＤＰＥ,但ＮＢＲ仍为分散相,ＨＤＰＥ为连续相,使该材料表现出热塑性。应力－应变性能和动态力学研究表明,该产品在室浊下表现出良好的弹性行为,且力学性能较好,但永久变形较大。     

动态硫化法制备三元乙丙橡胶/聚酰胺热塑性弹性体

采用动态硫化技术制备了三元乙丙橡胶(EPDM)／聚酰胺(PA)热塑性弹性体,研究了增容剂种类及用量、硫化体系及其用量、加料顺序、PA用量对其性能的影响,用扫描电镜分析了其相态结构。结果表明,用13份(质量份,下同)的氯化聚乙烯作为增容剂时,对该共混体系的增容效果最好;硫黄硫化体系是EPDM／PA热塑性弹性体的最佳硫化剂,当硫黄用量为2份时,既保证了该热塑性弹性体中的橡胶相能充分交联,又可避免过硫化对产品性能造成的负面影响;PA用量为35份的EPDM／PA热塑性弹性体具有良好的力学性能、耐溶剂性能和耐热老化性能;EPDM以平均粒径为2～5μm的粒子形态均匀分布于PA连续相中。     

三元乙丙橡胶/聚丙烯动态硫化热塑性弹性体的相态结构

用扫描电镜研究了三元乙丙橡胶(EPDM)聚/丙烯(PP)动态硫化热塑性弹性体(TPV)相态结构的形成过程,探讨了交联密度、制备工艺、螺杆转速对EPDM/PP TPV相态结构的影响。结果表明,采用以酚醛树脂为硫化剂的动态硫化工艺制备的EPDM/PP TPV,其相态结构实现了由EPDM和PP组成的双连续相到以EPDM为分散相、PP为连续相的转变;当硫化剂用量为7份时,橡胶相硫化速率和交联密度最大;当螺杆转速为180 r/m in时,反应性挤出工艺较之密炼机工艺制备的EPDM/PP TPV的橡胶粒子更细小、分散更均匀。     

Dynamic simulation and experimental evaluation of EPDM terpolymerization with vanadium-based catalyst

The development of a simplified kinetic model describing some effects observed in catalyzed olefin terpolymerization is presented. Based on the method of moments, the model describes the influence of Al/V ratio and diene concentration on reaction yield and on polymer characteristics such as molecular weight, ethylene incorporation, and polydispersity. In order to verify the model validity, the terpolymerization reactions were performed using VOCl₃–Al₂Et₃Cl₃ systems and 2-ethylidenebi-cyclo[2.2.1]hept-5-ene (ENB) as diene. The results of dynamic simulation fit well the experimental data for Al/V up to 15, but the model fails under high diene concentration, where branching reactions, neglected by reason of simplification, become significant. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 1173–1189, 1998     

热塑性聚氨酯弹性体合金研究进展

热塑性聚氯酯是一类具有良好耐低温、高弹性和耐磨性能的新型弹性体。笔者综述了热塑性聚氯酯弹性体合金的研究进展，分析了国内热塑弹性体生产现状及未来的发展趋势。     

HM型高效催化剂的乙烯聚合应用研究

研究组分为TiCl4/MgCl2-SiO2/AlR3的HM型高效催化剂的乙烯聚合，发现催化剂组分SiCl4有促进乙烯聚合的作用，并可以通过调节SiCl4用量控制催化剂Ti含量。ZnCl2有调节分子量的作用。由MgCl2-ZnCl2-SiO2复合载体组成的Ti系催化剂乙烯均聚催化效率为7．1014．0kg/g，聚合产物表观密度为0．23－0．30g.cm^2,20-200目颗粒质量为90％－95％。乙烯与1－丁烯共聚时催化效率大大提高，当1－丁烯的体积分数为10％时，效率高26．0kg/g，共聚产物熔点、结晶度随1-丁烯的体积分数增加而下降，而支化度则随之上升。HM催化剂1m^3反应釜工业试生产的试验结果表明，在05MPa下催化效率达152－241kg/g，聚合产物表观密度为0．33－0．34g/cm^3，20－200目颗粒质量为60．6％－84．3％，小于200目颗粒占1％以下。工业试生产的HM催化剂具有催化效率高、颗粒度均匀、极少细粉、表现密度大等优点，达到或超过了实验室研制的技术指标，具有优良的聚合性能。     

VMQ/LLDPE动态硫化热塑性弹性体的制备与性能

采用动态硫化法制备了甲基乙烯基硅橡胶(VMQ)/线形低密度聚乙烯(LLDPE)热塑性弹性体。考察了共混比、硫化剂种类、动态硫化时间对VMQ/LLDPE热塑性弹性体力学性能的影响,并研究了VMQ/LLDPE热塑性弹性体的热失重情况。结果表明:共混比为60/40、选用DBPH为硫化剂、动态硫化时间为5 min时,VMQ/LLDPE热塑性弹性体具有较好的力学性能。