Spherilene聚乙烯工艺

Spherilene工艺是以一系列高收率球形催化剂为中心的。这些催化剂可生产范围广的LLDPE,其密度为0.890～0.970,分子量从特殊的流动性牌号到超高分子量。目前有3种催化剂是有效的:201适用于生产分子量范围宽、颗粒直径为1000～3000#m的HDPE;202适用于生产分子量分布窄,颗粒直径为1000～3000μm的HD-LLDPE;GF1适用于生产分子量分布窄或宽、晶状颗粒尺寸为100～1500μm的HDPE。     

热分析评价EPS30R的性能

采用热重分析法测试1#和2#EPS30R的残存量分别为1.13%和0.59%,这些残留物是生产过程中使用的金属催化剂和填充物的残留。差示扫描量热法和动态热机械分析法测试结果显示,1#和2#样品的熔融半峰宽分别为11.4℃和16.7℃,1#样品非晶乙丙橡胶相具有更低的玻璃化转变温度和较窄的转变峰宽,由此推测,1#样品有相对低的分子量,分子量分布较窄,GPC结果显示,1#和2#样品的MN分别为9.95万和10.42万,多分散指数(D)分别为3.69和3.89;1#和2#样的结晶度分别为42.6%和40.8%,在常温区1#样品的储能模量比2#样品高,1#和2#的弯曲弹性模量分别为1 037 MPa和972 MPa,热分析表征与力学性能测试结果一致。     

ATRP法合成低摩尔质量BPS的研究

采用ATRP法合成了一系列摩尔质量低（Mn=5×10^3～1×10^4g／mol）、分布窄（Mw／Mn=1．8～2．2）的聚苯乙烯（PS）,通过均相催化溴化法制得一系列摩尔质量低、分布窄、溴含量不同的溴化聚苯乙烯（BPS）,其中溴的质量分数最高可达75．59％,热分解温度达396℃。     

从分子量分布探討均相及非均相丁二烯顺式-1,4聚合的机理

本工作以逐步沉淀法测定了在均相（Et_2AlCl-CoCl_2·4C_5H_5N）及非均相（i-Bu_3Al-TiI_4）Ziegler型催化剂的作用下,丁二烯在各种条件下进行顺式-1,4聚合的分子量分布。结果指出,不论均相或非均相催化聚合得到的分子量分布都比较窄。对于均相体系,升高聚合温度、降低单体浓度、添加链转移剂（如乙硫醚、N-苯基-β-萘胺、庚烷）、减少催化剂钴的浓度和增加Al/Co比,均能使聚合物的分子量分布变窄;而对于非均相体系,则降低聚合温度和减少Al/Ti比均能增加分子量的均一性;单体浓度和催化剂老化对分子量分布无显著影响。 非均相聚合的分子量分布比均相聚合的更窄,前者的微分分布曲线的高峰偏于高分子量部分,而后者的偏于低分子量部分。这可能是由于非均相聚合的链终止速度依赖于链长,而均相聚合的链终止速度与链长无关。     

凝胶渗透色谱测定窄分布聚合物的分子量分布

我们使用ARL 950型仪器,选用排斥极限为50—2×10~6A柱组,以ARL公司提供的聚苯乙烯(ARL-PS)为标样,建立校准线,对本院采用阴离子溶液法聚合的窄分布中、低分子量的聚苯乙烯(LHY-PS)和低顺式聚丁二烯(LHY-LPB)样品的分子量及其分布进行了测定。同时,对     

分子量分布对低密度聚乙烯光氧老化特性的影响

采用衰减全反射红外光谱技术（ATR-FTIR）、热重分析法（TG）、凝胶渗透色谱（GPC）、扫描电子显微镜（SEM）和力学试验比较研究了不同分子量分布指数低密度聚乙烯（LDPE）的光氧老化特性,分析了分子量分布对LDPE化学结构、热稳定性、平均分子量、表面微观形貌和力学性能的影响规律。结果表明分子量分布越宽,LDPE不饱和度增长越剧烈,支化作用增长越显著;分子量分布越窄,羰基指数增长越快;分子量分布对于分子结构的断链行为并无影响。分子量分布指数越大,LDPE起始热分解温度和失重5%对应温度下降更快,热稳定性更容易变差,平均分子量下降更多,表面微观形貌老化现象越严重;弯曲强度和冲击强度受影响更显著,指数为6.0的LDPE老化24 d冲击强度就已丧失。分析认为,分子量越大、分布越窄表明分子链越长、短分子链越少,与氧接触而产生自由基的概率也越小,因此聚乙烯分子量分布越宽,材料越容易老化。     

充油溶聚丁苯橡胶2564 A的微观结构与性能

研究了溶聚丁苯橡胶(SSBR,牌号为2564 A)的微观结构与性能,并与牌号为5025-2的SSBR及乳聚丁苯橡胶(ESBR,牌号为1712)进行了对比。结果表明,与ESBR 1712相比,SSBR 2564 A生胶的数均分子量和重均分子量大,分子量分布窄,乙烯基和顺式结构含量高、反式结构含量低,混炼胶的硫化速率慢,硫化胶的物理机械性能略差,耐老化性能、压缩生热性能及炭黑分散性优;与SSBR 5025-2相比,SSBR 2564 A生胶的数均分子量、重均分子量及分子量分布相当,乙烯基含量高,顺式结构含量略高,反式结构含量低,混炼胶的结合胶含量高,交联密度相当,硫化速率略快,硫化胶的物理机械性能相当,耐老化性能优,压缩生热性能及炭黑分散性相当。     

不同牌号丁苯橡胶的结构与性能对比

对不同牌号丁苯橡胶的微观结构、分子量及其分布、硫化胶的物理机械性能、混炼胶的硫化特性、压缩永久变形及动态力学性能进行了对比.结果表明,溶聚丁苯橡胶(SSBR)与乳聚丁苯橡胶(ESBR)的乙烯基、反式-1,4-结构及顺式-1,4-结构含量差别较大.SSBR的相对分子质量更高,分子量分布更窄,硫化速率更快,耐磨性能、抗湿滑...     

新牌号乙丙弹性体

据《RubberWorld》1996，214（6）：53报道，Eneohem公司开发出牌号为DutralTS6040的乙丙弹性体。该弹性体适用于生产结构复杂的型材，其制品尺寸稳定，生产成本低。其生胶和硫化胶均具有优异的抗塌陷性和尺寸稳定性，硫化时间短，挤出速度快。该产品具有非常高的相对分子质量和窄相对分子量分布，并具有中高丙烯含量和高亚乙基降冰片烯含量。该弹性体适合制备型材、如汽车用挡风条、消音器、窗口密封件等。新牌号乙丙弹性体     

离子液体中ATRP法合成聚合物分子量控制

在氯化1-烯丙基-3-甲基咪唑（[AMIM]Cl）离子液体中,采用原子转移自由基聚合（ATRP）技术,以CuBr/乙二胺为催化体系,合成了分子量分布窄的聚甲基丙烯酸甲酯（PMMA）分子。探索了聚合反应条件对PMMA分子量大小及分布的影响。通过GPC对PMMA分子量大小及分布进行测试,结果表明,在[AMIM]Cl离子液体体系中的ATRP反应,反应时间是控制PMMA分子量大小主要因素,而催化体系是控制PMMA分子量分布宽窄的决定性因素。通过优化反应条件可以设计聚合物分子量的大小和分布,可以实现对聚合物分子量的精确控制,使合成的聚合物材料满足在化工医药中的特定应用。     

Copolymerization of carbon dioxide and propylene oxide with zinc glutarate as catalyst in the presence of compounds containing active hydrogen

To enhance the catalytic copolymerization of CO₂ and propylene oxide catalyzed by zinc glutarate, the influence of trace of water, ethanol, and propanal on the catalytic activity, the resulted copolymer structure, and the molecular weight and molecular weight distribution of the copolymer were investigated extensively. The experimental results showed that the catalytic activity decreased remarkably in the presence of either trace of ethanol or water, but increased in the presence of trace of propanal. Both ¹H‐NMR and ¹³C‐NMR spectra suggested that the content of carbonate linkages of resulted copolymer was not effected obviously in the presence of above‐mentioned impurities, giving completely alternating poly(propylene carbonate) (PPC). GPC results indicated that these impurities reduced the molecular weights but broadened the molecular weight distributions of resulted copolymers. Finally, the byproduct contents including both propylene carbonate determined by GC and polyether increased with the increase of three impurity concentrations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Copolymerization of propylene oxide and carbon dioxide in the presence of diphenylmethane diisoyanate

To improve the thermal and mechanical properties of poly(propylene carbonate) (PPC), the copolymerization of CO₂ with PO was successfully carried out in the presence of a third monomer, 4,4′-diphenylmethane diisocyanate (MDI) using supported multi-component zinc dicarboxylate as catalyst. Chemical structure, the molecular weight, as well as thermal and mechanical properties of the resulting new copolymers were fully investigated. The experimental results show that the yield increases with increasing MDI feed content from 0 to 2 wt.%. The introduction of MDI leads to an increase in the molecular weight of PPC with light crosslinking. When the MDI feed content is lower than 3 wt.%, the PPC copolymers have number average molecular weight (Mn) ranging from 153 K to 424 K g/mol and molecular weight distribution (MWD) values ranging from 1.71 to 2.79. The resulting PPC copolymers show higher glass transition temperature (Tg) and decomposition temperature compared with poly(propylene carbonate) (PPC) without MDI. Considering the gel content of the resulting copolymers, the optimized MDI feed content should be smaller than 1.5 wt.% based on PO content. The introduction of small amount of MDI provides a very effective way to improve the mechanical properties and thermal stabilities of PPC due to the increase in its molecular weight.     

Synthesis and characterization of linear asymmetrical poly(propylene oxide) diol

Linear asymmetrical poly(propylene oxide) was synthesized through four‐step reactions: selective benzylation, alcohol exchange reaction, propylene oxide anionic polymerization, debenzylation. One terminal of the asymmetrical polymer chains is alcohol hydroxyl and the other is phenol hydroxyl. It was characterized with infrared (IR) and ¹H Nuclear Magnetic Resonance (¹H‐NMR). Peaks at 1.11, 3.38, and 3.53 ppm were attributed to side groups (? OCH₂CH(CH₃)? ), backbone units (? OCH₂CH(CH₃)? ) and (? OCH₂CH(CH₃)? ) of poly(propylene oxide), respectively. Molecular weight and molecular weight distribution were measured with ¹H‐NMR and laser light scattering (LLS), which showed that the linear asymmetrical poly(propylene oxide) was mono‐disperse (PDI = 1.02–1.07). Then, its carbamate reaction with phenyl isocyanate was studied; the reaction rate constants for phenol hydroxyl and alcohol hydroxyl of poly(propylene oxide) were k₁ = 0.209 mol L^?1 min^?1 and k₂ = 0.051 mol L^?1 min^?1. There was a great reactivity difference for two types of hydroxyls in asymmetrical poly(propylene oxide), contrasting to the single carbamate reaction rate constant of symmetrical poly(propylene oxide) (k₃ = 0.049 mol L^?1 min^?1). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis of polyether-based block copolymers based on poly(propylene oxide) and terephthalates

Poly(propylene oxide) (PPO) is a low reactive telechelic polyether and the synthesis of high molecular weight poly(propylene oxide)-based block copolymers was studied. The poly(propylene oxide) used was end capped with 20 wt % ethylene oxide and had a molecular weight of 2300 g/mol (ultra-low monol PEO-b-PPO-b-PEO). The type of terephthalic acid based precursors was varied: terephthalic acid, dimethyl terephthalate, diphenyl terephthalate, di(trifluoro ethyl) terephthalate, di(p-nitrophenyl) terephthalate) and terephthalic acid chloride. High molecular weight poly(propylene oxide) based segmented block copolymers were obtained with diphenyl terephthalate (inherent viscosity: 1.6 dl/g).The synthesis of polyether(ester-amide)s comprising PPO and isophthalamide-based segments was also studied by varying the polymerization temperature and time. High molecular weight poly(propylene oxide) block copolymers could be obtained if the reaction was carried out for 2 h at 250 °C under vacuum. Higher temperatures (280 °C) and longer times result in lower inherent viscosities, probably due to degradation of the polyether.     

Fractionation of partially stereoregular poly(propylene oxide)

Partially stereoregular poly(propylene oxide) samples were synthesized via reactions catalysed by a preformed analytically defined trimethylaluminium hydrolysate. These samples were fractionated into two contrastingly different fractions.

1. (i) D-polymers: This fraction constituted the major part (up to 90%). It mainly contained cyclic low molecular weight oligomers (MW < 1000). The linear chains found in D-polymers had hydroxyl end groups. No double bonds could be detected spectroscopically.

2. (ii) K-polymers: This fraction was high molecular weight stereoregular polymer. Stepwise thermal precipitation from dilute isooctane solution of K-polymers yielded a succession of fractions which differed in melting point. It appears that the phase equilibria during the thermal precipitations were not controlled by the molecular weights of species.

FI Catalysts: A New Family of High Performance Catalysts for Olefin Polymerization

This paper reviews a new family of olefin polymerization catalysts. The catalysts, named FI catalysts, are based on non‐symmetrical phenoxyimine chelate ligands combined with group 4 transition metals and were developed using “ligand‐oriented catalyst design”. FI catalysts display very high ethylene polymerization activities under mild conditions. The highest activity exhibited by a zirconium FI catalyst reached an astonishing catalyst turnover frequency (TOF) of 64,900 s ^–1 atm ^–1, which is two orders of magnitude greater than that seen with Cp₂ZrCl₂ under the same conditions. In addition, titanium FI catalysts with fluorinated ligands promote exceptionally high‐speed, living ethylene polymerization and can produce monodisperse high molecular weight polyethylenes (M_w/M_n<1.2, max. M_n>400,000) at 50 °C. The maximum TOF, 24,500 min ^–1 atm ^–1, is three orders of magnitude greater than those for known living ethylene polymerization catalysts. Moreover, the fluorinated FI catalysts promote stereospecific room‐temperature living polymerization of propylene to provide highly syndiotactic monodisperse polypropylene (max. [rr] 98%). The versatility of the FI catalysts allows for the creation of new polymers which are difficult or impossible to prepare using group 4 metallocene catalysts. For example, it is possible to prepare low molecular weight (M_v∼10³) polyethylene or poly(ethylene‐co‐propylene) with olefinic end groups, ultra‐high molecular weight polyethylene or poly(ethylene‐co‐propylene), high molecular weight poly(1‐hexene) with atactic structures including frequent regioerrors, monodisperse poly(ethylene‐co‐propylene) with various propylene contents, and a number of polyolefin block copolymers [e.g., polyethylene‐b‐poly(ethylene‐co‐propylene), syndiotactic polypropylene‐b‐poly(ethylene‐co‐propylene), polyethylene‐b‐poly(ethylene‐co‐propylene)‐b‐syndiotactic polypropylene]. These unique polymers are anticipated to possess novel material properties and uses.     

UV-curable water-borne polyurethane primers for aluminum and polycarbonate interfaces

Water-borne polyurethane (WPU) primers were synthesized from three types of polyol, viz., poly(propylene glycol), poly(tetramethylene glycol), and polycaprolactone diol (PCL) at two prepolymer molecular weights, and were tested for the adhesion between vinyltrimethoxysilane modified aluminum panel and polycarbonate. It was found that chemical hybridizations of Al panel with WPU via sol–gel reaction were crucial to enhance the adhesion. Among three types of polyol, PCL gave the highest adhesion strength, glassy and rubbery moduli, tensile strength, and glass transition temperature. On the other hand, smaller prepolymer molecular weight gave improved adhesion and improved mechanical properties due to the increased crosslink density and cohesive strength.     

Liquid Pool Copolymerization of Propylene/1‐Butene with a MgCl2‐Supported Ziegler‐Natta Catalyst

Summary: Liquid pool propylene/1‐butene copolymerizations were carried out in a batch reactor with a high activity Ziegler‐Natta catalyst system. Experimental runs were performed to evaluate the effect of the 1‐butene content on the crystallinity and melt temperature of the polymer resins. According to the results, 1‐butene can be significantly incorporated into the polymer chain at high polymerization rates over the whole range of copolymer compositions, leading to a decrease in the melting temperature (T_m) of the polymer, when compared to the poly(propylene) homopolymer, allowing for reduction of the sealing initiation temperature. It was observed by GPC and MFI measurements that the average molecular weights and the polydispersity index of the copolymer significantly decreased when compared to the ones obtained from poly(propylene). Despite high polymerization rates, polymer particles with good morphological features were produced in all cases. It was also observed that the absence of an external electron donor led to low crystallinity values for both the poly(propylene) homopolymer and for copolymers with different fractions of 1‐butene, when compared to literature values frequently reported for polymer resins based on 1‐butene and propylene. The obtained results indicate that a family of bulk propylene/1‐butene copolymer grades can be successfully developed for packaging and film applications.

Surface morphology and molecular weight distribution (deconvoluted into Schulz‐Flory distributions) of the propylene/1‐butene copolymer.     

湿气固化硅烷封端聚氨酯的结构与性能

利用3-异氰酸酯基丙基三甲氧基硅烷(KH901)与聚氧化丙烯二醇(PPG)端羟基的封端反应,合成了可湿气固化硅烷封端聚氨酯(STPU)。探讨了硬段含量、PPG分子量与树脂黏度、胶膜硬度和力学性能之间的关系,建立了STPU封端效率的表征方法。结果表明:提高PPG分子量会降低封端效率,增加树脂黏度,提高固化后胶膜的断裂伸长率;将过量PPG8000与异佛尔酮二异氰酸酯(IPDI)预聚,再与KH901反应,可制备高分子量STPU,但分子量分布较宽,黏度较大,固化后胶膜的断裂伸长率为140%;通过高分子量PPG18000与KH901的直接反应封端,合成的STPU黏度适中,胶膜断裂伸长率达240%,且合成步骤简单。     

Structure–property relationships of poly(urethane–urea)s with ultra-low monol content poly(propylene glycol) soft segments. Part II. Influence of low molecular weight polyol components

Segmented poly(urethane–urea)s have been synthesized with mixed soft segments of ultra-low monol content poly(propylene glycol) (PPG) and tri(propylene glycol) (TPG) which allows the fabrication of quality elastomers without crosslinking. The narrow molecular weight distribution of the ultra-low monol content PPG polyols allows for the probing of the influence of the low molecular components of the molecular weight distribution through the inclusion of low molecular homologs of PPG such as TPG. Structure–property relationships for these materials were investigated as average soft segment molecular weight was varied by blending 8000 g/mol PPG with TPG to achieve molecular weights of 2500, 2000, and 1500 g/mol. Morphological features such as microphase separation, interdomain spacing and interphase thickness were quantified and revealed with SAXS. AFM was utilized to verify the microphase separation characteristics inferred by SAXS. The thermal and mechanical behavior was assessed through applications of DMA, DSC, and conventional mechanical tests. It was found that as the average soft segment molecular weight was decreased through the addition of TPG, the interdomain spacing distinctly increased contrary to the trend seen for decreasing soft segment molecular weight in PPG based systems without TPG. Additionally, the inclusion of TPG in the poly(urethane–urea) formulations resulted in the formation of larger hard domains as evidenced by AFM. These results and supporting evidence from DMA, DSC, birefringence, and mechanical testing led to the conclusion that TPG apparently acts more as a chain extender as well as, or in contrast to, a soft segment.