FI催化剂在制备乙烯基共聚物中的应用

综述了带有芳氧基亚胺配体的ⅣB族金属络合物(FI催化剂)催化的乙烯类共聚合。Ti-FI催化剂可用于乙烯与α-烯烃、乙烯与环烯烃的共聚合。相比传统的茂金属催化剂,FI催化剂可以制备共聚单体含量更高的共聚物。FI催化剂对极性基团具有良好的耐受性,将其用于乙烯与极性单体的共聚合,可取得理想的效果。与亚胺N原子相连的芳香环上的邻位H原子被F原子所取代的Ti-FI催化剂催化乙烯类聚合时,表现出活性聚合的特征。因此可通过控制单体加入顺序制备嵌段共聚物。用两种不同的FI催化剂,且以二乙基锌为链穿梭剂,可制备多嵌段共聚物。优化配体结构可制备高效的乙烯类共聚合催化剂。这些将有利于实现聚烯烃的功能化和高性能化。     

不同催化体系乙丙共聚合技术研究

采用自制催化剂及进口催化剂为主催化剂,烷基铝为助催化剂,对乙烯、丙烯、乙叉降冰片烯三元共聚合体系进行了对比技术研究,研究结果表明,2种催化剂催化乙丙三元共聚合时聚合规律相同,催化活性相当,并且2种催化剂合成的乙丙橡胶样品性能指标相当。     

乙烯聚合新工艺及产品特性

采用间歇聚合试验装置模拟了乙烯聚合新工艺(淤浆均聚合-离心分离-气相共聚合)的流程.考察了新工艺的可行性,研究了新工艺的技术特点及产品特性,并将采用新上艺制备的试样与工业生产PE80及PE100级双峰分布聚乙烯进行比较.结果表明:第一段淤浆聚合后脱除溶剂不影响第二段的气相共聚合活性,该工艺是可行的;通过模拟不同的工艺表...     

钒化合物催化活化体系乙丙三元共聚合研究

采用自制的钒化合物为主催化剂,倍半烷基铝为助催化剂,三氯乙酸乙酯为活化剂,对乙烯、丙烯、乙叉降冰片烯三元共聚合进行了研究,结果表明,当活化剂采用三氯乙酸乙酯时乙丙三元共聚合活性要高于其它活化剂,在活化剂存在条件下,当活化剂与钒催化剂的物质的量比为12、催化剂用量为0.06mmol/(100 mL己烷)、铝比n(Al)/n(V)=40、聚合温度为常温时,乙丙三元聚合活性可提高3.1倍左右。     

乙烯与极性单体共聚的研究进展

综述了采用齐格勒-纳塔催化剂、茂金属催化剂和后过渡金属催化剂等通过乙烯与极性单体共聚合反应制备功能性聚乙烯的研究进展,简述了催化剂类型与结构对催化活性以及产物结构的影响。研究包括超支化功能性聚乙烯合成、乙烯与醇、酯类极性单体共聚合、乙烯与降冰片烯共聚合、乙烯与硅烷单体共聚合及乙烯与甲基丙烯酸甲酯共聚合等。     

BCE型催化剂的共聚合性能

采用分光光度计、粒径分析仪等表征了BCE型催化剂的组成、粒径和形态等;采用核磁共振仪、高温凝胶渗透色谱仪等研究了催化剂的共聚合性能,并与参比催化剂进行了比较。结果表明:BCE型催化剂的聚合活性达16.6 kg/(g·h),较参比催化剂高约8%;所制聚乙烯(PE)的堆密度为0.34 g/cm3,粒径≥75~830μm的粉料质量占PE总质量的97.2%;BCE型催化剂的共聚合性能更好,用其催化乙烯和1-丁烯共聚合时,有更多的1-丁烯插入到高相对分子质量部分,有利于提升所制管材的力学性能。     

乙烯和/或1-丁烯与丙烯共聚合的工业化研究

分析了Sphripol-Ⅱ环管工艺引入丙烯、乙烯及1-丁烯共聚单体后的聚合特性。引入乙烯后催化剂活性增加,氢调敏感性变差。引入1-丁烯后,催化剂活性变化不大,链转移速率增加,需降低H2用量以确保无规共聚PP的熔体流动速率合格。引入乙烯和1-丁烯的三元共聚合催化剂活性提高,氢调敏感性与乙烯和丙烯的二元共聚合时相当;因闪蒸线蒸汽压力的限制,装置负荷降低30%;控制环管反应器内淤浆中可溶物的含量,调整反应温度为60.0℃,乙烯质量分数≤2.5%;控制汽蒸器内温度低于105.0℃,避免低分子物料熔融黏附在汽蒸器表面及干燥器表面。     

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。     

TiCl_4/NiCl_2/SiO_2催化剂制备宽峰分布PE的研究

以SiO_2为载体,依次加入NiCl_2或Ni(NO_3)_2、给电子体,然后负载TiCl_4,制备多相齐格勒-纳塔催化剂,以三乙基铝为助催化剂,催化乙烯均聚合及乙烯-1-己烯共聚合,均可得到宽峰分布聚乙烯(PE)。考察了NiCl_2或Ni(NO_3)_2加入量、给电子体结构与加入量、聚合温度及1-己烯加入量对催化性能的影响,并考察了催化剂的氢调敏感性。结果表明:m(NiCl_2)/m(SiO_2)为1:10,2-氯吡啶与SiO_2的摩尔比为为1:10时,80℃下陔催化剂体系可高效催化乙烯聚合,催化效率达3.5 kg/g,PE的相对分子质量分布(M_w/M_n)为15.8;在相同条件下催化乙烯-1-己烯共聚合时,1-己烯加入量为15 mL,其催化效率可达3.7 kg/g,共聚物的M_w/M_n为16.9。     

氟乙烯共聚物

氟乙烯与其他单体共聚合,这是改性聚氟乙烯的最佳方弦。研究该反应不仅对评价单体的反应能力,弄清反应机理以及研究共聚物的结构和性质,而且对制造新型聚合材料都有重要意义。氟乙烯与含氟单体共聚合氟乙烯可与全氟化和不完全氟化的烯烃     

乙丙橡胶生产工艺与技术

乙丙橡胶以其独特的性能,在汽车工业、建筑行业、油品添加剂、塑胶跑道等领域有广泛的应用。本文主要介绍了乙丙橡胶生产技术、乙丙橡胶产品牌号、性能以及应用领域,结合现有的乙丙橡胶科研情况,阐述了乙丙橡胶催化剂的研发、核壳型球状乙丙橡胶、原位聚合法合成长链支化乙丙橡胶、乙烯、丙烯与其他二烯烃的共聚物研究进展;详细研究了乙丙橡胶溶液聚合工艺技术中的聚合技术、单体回收技术、失活洗涤技术、闪蒸提浓技术以及国外公司在中国建设装置的生产技术情况。提出了乙丙橡胶的关键生产技术是乙丙橡胶聚合所采用的催化剂体系,通过催化体系的更新换代,开发不同用途的乙丙橡胶,以满足开发高性能材料的要求。在此基础上,指出了今后乙丙橡胶新的催化体系开发将成为未来的研究重点。     

Study on morphology of ternary polymer blends. II. Effect of composition

The composition effect on morphology of polypropylene/ethylene–propylene–diene terpolymer/polyethylene (PP/EPDM/PE) and polypropylene/ethylene–propylene–diene terpolymer/polystyrene (PP/EPDM/PS) ternary blends has been investigated. In all of the blends, polypropylene as the major phase was blended with two minor phases, that is, EPDM and PE or PS. From morphological studies using the SEM technique a core–shell morphology for PP/EPDM/PE and separated dispersed morphology for PP/EPDM/PS were observed. These results were found to be in agreement with the theoretical predictions. The composition of components affected only the size of dispersed phases and had no appreciable effect on the type of morphology. The size of each dispersed phase, whether it forms core or shell or disperses separately in matrix, can be related directly to its composition in the blend. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1138–1146, 2001     

Structure and properties of organoclay/EPDM nanocomposites: Influence of ethylene contents

Four organoclay (OC)/ethylene–propylene–diene rubber (EPDM) nanocomposites with different ethylene contents were prepared by melt blending. X‐ray diffraction spectrum (XRD) and transmission electronic microscope (TEM) photos showed that OC/EPDM nanocomposites were intercalated, and the ethylene content had little influence on the dispersion of OC. The addition of OC prolonged the optimum cure time and reduced the crosslink density of OC/EPDM. The improvement in tensile strength of OC/EPDM nanocomposites with high ethylene contents (67–70%) was larger than that of OC/EPDM nanocomposites with low ethylene contents (52–52.5%). XRD results of the stretched samples testified that the extension promoted orientation of silicate layers, and induced crystallization of polyethylene (PE) segments in OC/EPDM nanocomposites with high ethylene contents. The highly oriented micro‐fibrillar structure and more oriented amorphous chains, which resulted from strain‐induced crystallization of PE segments and the orientation of clay layers in OC/EPDM nanocomposites with high ethylene contents (67–70%), should be responsible for larger improvement in tensile strength than that of those nanocomposites with low ethylene contents (52–52.5%) © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 914–919, 2006     

Synthesis and photodegradable properties of methyl vinyl ketone–EPDM–styrene graft terpolymer

The graft terpolymerization of methyl vinyl ketone (MVK) and styrene (St) onto ethylene–propylene–diene terpolymer (EPDM) was carried out under various polymerization conditions. The synthesized graft terpolymer, MVK–EPDM–St (MVES), was identified by infrared (IR) spectroscopy. The effects of monomer concentration, mole ratio of MVK to St, reaction time, reaction temperature, and initiator concentration on the graft terpolymerization were examined. Upon UV irradiation in the presence of oxygen, the MVES-containing carbonyl group showed photodegradable properties caused by Norrish type II reaction. The new IR characteristic peaks, such as carbonyl, vinyl, and hydroxy groups of the photodegraded MVES, increased with increasing UV irradiation time. The tensile strength and elongation at break of MVES after UV irradiation were lower than those of before UV irradiation. The color difference of the irradiated MVES was higher than that of EPDM. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67:1721–1727, 1998     

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     

载体包裹填料提高PE/PP/EPDM/BN材料导热性

以三元乙丙橡胶(EPDM)/氮化硼(BN)复合材料为母料,通过熔融共混EPDM/BN复合材料与聚乙烯(PE)、聚丙烯(PP),制备PE/PP/EPDM/BN复合材料。采用PE∶PP的比例为5∶5,以使复合材料形成共连续结构;通过EPDM包裹BN的方法,实现BN在PE/PP/EPDM/BN复合材料共连续结构的相界面处分布,以形成导热通路,从而提高PE/PP/EPDM/BN复合材料的导热性能。通过接触角测试和扩散系数公式计算预测了EPDM会选择性分布在PE/PP/EPDM复合材料共连续结构的相界面处。通过连续度计算结果得出,EPDM为PE和PP总质量的15%时,EPDM的连续度为85.3%。由扫描电子显微镜分析表明EPDM在PE/PP/EPDM/BN复合材料中连续贯通。由导热测试分析知,随着BN含量的增加,PE/PP/EPDM/BN复合材料的热导率逐渐增加。这项研究提高了PE/PP复合材料的热导率,此材料在电子工业中可能具有潜在应用。     

PTC effect in carbon black‐filled ethylene–propylene–diene terpolymer systems

The positive temperature coefficient (PTC) effects of carbon black (CB)‐filled semicrystalline and amorphous ethylene–propylene–diene terpolymer (EPDM) composites were studied. The semicrystalline EPDM/CB composite exhibited a low PTC effect followed by a pronounced negative temperature coefficient (NTC) effect, while the amorphous EPDM/CB composite exhibited only an NTC effect. By the effect of γ‐ray irradiation, not only was the NTC effect of the composites eliminated, but also a high PTC effect appeared. The PTC intensity reached as high as six orders of magnitude even for an amorphous EPDM/CB composite and the PTC transition temperature decreased with the irradiation dose. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1571–1574, 2001     

Dynamic vulcanisation of EPDM/PE-based thermoplastic vulcanisates studied along the extruder axis

Simple blending and dynamic vulcanisation of EPDM/PE blends using the resol/SnCl₂ system was studied in an extruder using a series of sampling devices. The melting of the PE pellets occurs just in front of and in the first kneading zone. Upon complete melting of the PE phase, the EPDM/PE blends reach very quickly their final morphology. Crosslinking of the EPDM phase to high levels occurs already when the PE phase is not yet fully molten. The higher the EPDM content, the higher the viscous dissipation, the higher the melt temperature and, consequently, the higher the crosslinking rate. For the EPDM/PE (50/50; w/w) TPV a transition from continuous via co-continuous to fully dispersed EPDM is observed, which is driven by crosslinking. Although the degree of crosslinking of the EPDM rubber is very high, this does not prevent phase inversion of the blend. The EPDM/PE interface is rather blurred, because PE crystalline lamellae are growing into the EPDM domains, probably because of the high compatibility between PE and EPDM (60 wt% of ethene). This study shows that dynamic vulcanisation in extruders proceeds quite differently from that in batch kneaders, where melting, mixing and crosslinking are separated in time. In extruders mass and heat transport, melting of the thermoplastic, morphology development (including dispersion and phase inversion), distribution and dissolution of (crosslinking) chemicals and crosslinking of the rubber do not occur as independent phenomena, but mutually and/or continuously interact.     

乙丙橡胶新品种及应用技术进展（二）

过氧化物硫化体系EPDM具有较好的耐热性能和较小的压缩永久变形,但焦烧时间偏短。Arkema公司开发了2种新的过氧化物交联技术¨引,分别称作SP（焦烧保护）和CST（速度控制）技术,能非常有效地避免胶料焦烧。与普通EPDM相比,Arkema公司的F40M—SP和F—CST牌号的EPDM焦烧时间延长3倍以上;在相同的温度下,F—CSTEPDM固化速度快,可以提高生产效率和节约生产成本。