新型乙烯—硅氧烷共聚物的合成及润滑性研究

发布时间：2018-01-17 20:03

本文关键词：新型乙烯—硅氧烷共聚物的合成及润滑性研究　出处：《浙江大学》2017年博士论文　论文类型：学位论文

【摘要】：聚烯烃价格低廉、综合性能优良,是应用最广泛的通用塑料。然而,由于缺乏功能基团,传统的聚烯烃产品难以满足日益多样化的性能需求,因此对聚烯烃的功能化改性具有重要的研究意义和广泛的工业影响。有机硅是以Si-O为主链、甲基为侧链的兼具有机-无机特性的化合物,具有分子链柔顺性好、表面张力极低、热稳定性良好等特点。然而,有机硅的机械性能不足,与碳基材料的相容性差。将聚烯烃和有机硅结合,设计并合成聚烯烃与有机硅的嵌段或者接枝共聚物,能有效集成聚烯烃机械性能良好、与碳基材料相容性好和有机硅分子链柔顺性好、表面张力低的优点,尤其适合用作聚烯烃加工的复合润滑剂。本文首先设计并合成了三种新型乙烯-硅氧烷共聚物,分别是含硅乙烯共聚物、聚二甲基硅氧烷-g-聚乙烯共聚物和聚乙烯-b-聚烷基硅氧烷-b-聚乙烯共聚物。然后将这三种乙烯-硅氧烷共聚物用作HDPE加工的复合润滑剂,研究了不同共聚物结构对HDPE本体性能和表面性能的影响。主要内容包括:(1)设计并制备了一种新型低极性含硅大单体(OO7),通过乙烯与大单体的配位共聚反应,合成了含硅乙烯共聚物(E-co-007)。研究了两种催化体系——rac-EtInd2ZrCl2/MAO 和 VCl3(THF)3/Et2AlCl 的聚合行为,发现 OO7 对配位共聚催化剂的毒害作用远低于其他种类的有机硅大单体。随着OO7加入量从80 mmol/L增大至280 mmol/L,E-co-OO7的共单体插入率从1.7 mol%增大至5.6 mol%,重均分子量从22700 g/mol降低至10700 g/mol,分子量分布指数从2.6下降至1.7。热性能研究表明,E-co-OO7共单体含量越高,其玻璃化温度越低(-76.1～-64.0℃),结晶性能越弱。(2)通过低含氢硅油与单末端双键聚乙烯(vPE)的硅氢加成反应,首次合成了聚二甲基硅氧烷-g-聚乙烯共聚物(PDMS-g-PE)。低含氢硅油含氢量越高,接枝上的PE支链越多,所得PDMS-g-PE的分子量越大(重均分子量为69800～82900g/mol,分子量分布指数为2.8～4),同时硅氧烷含量越低(27～46wt%)。热性能研究表明,PDMS-g-PE玻璃化温度极低(-124.5～-118.2℃),而且共聚物的硅氧烷含量越低,其玻璃化温度越高,结晶性能越强。(3)制备了一系列含有不同链长硅氧烷、分子量相近的聚烷基硅氧烷(PHSX),通过PHSX与vPE的硅氢加成反应,合成了新型聚乙烯-b-聚烷基硅氧烷-b-聚乙烯共聚物(PE-b-PHSX-b-PE)。共聚物的重均分子量为16100～18700 g/mol,分子量分布指数为1.5～1.7,硅氧烷含量为21～48wt%。热性能研究表明,PE-b-PHSX-b-PE中硅氧烷链段越长,其玻璃化温度越低(-120.5～-89.0℃),结晶性能越弱。相形态研究表明,经退火操作后,共聚物的表面和本体相形态都呈现层状相分离。(4)研究了以上三种乙烯-硅氧烷共聚物作为HDPE复合润滑剂的应用效果,结果表明:加入少量(2%,5%或10%)乙烯-硅氧烷共聚物使HDPE的流动性能提高,弹性模量和拉伸强度降低,断裂伸长率提高,部分缺口冲击强度提高,同时使其表面张力、摩擦系数和磨损率降低。含有最长硅氧烷链段的嵌段共聚物PE-b-PHSX15-b-PE具有最好的内润滑性和外润滑性,其共混物(加入量5%)的熔融指数(2.53g/10min)比纯HDPE高81%,水接触角(106°)比纯HDPE高]8%,摩擦系数(0.047)比纯HDPE低35%,磨损率(5.2 × 10-3 mm3/Nm)比纯HDPE低53%。与常用的润滑剂(硅氧烷母料或者聚乙烯蜡)相比,乙烯-硅氧烷共聚物在内、外润滑性、力学性能和热稳定性方面具有全方位的优势。
[Abstract]:Polyolefin low price, excellent performance, is the most widely used general plastics. However, due to the lack of functional groups, the traditional performance of polyolefin products is difficult to meet the increasingly diverse needs of the industry, so the functional modification of polyolefin has important significance and broad. Silicone is Si-O as the backbone for methyl both organic and inorganic compound properties of side chain, with the chain flexibility is good, extremely low surface tension, thermal stability. However, insufficient mechanical properties of silicone, and carbon based materials. The poor compatibility of polyolefin and silicone combined block or graft copolymers were designed and synthesized with silicone polyolefin that can effectively integrated polyolefins with good mechanical properties, good biocompatibility and good flexibility of the silicone molecular chain and carbon based materials, the advantages of the Zhang Lidi surface, especially suitable for adding polyolefin Composite lubricant workers. This paper design and three novel vinyl siloxane copolymers were synthesized, respectively is silicon containing ethylene copolymer, poly two methyl siloxane polyethylene and polyethylene copolymer -g- -b- poly siloxane -b- polyethylene copolymer. Then the composite lubricant three vinyl siloxane copolymer used for HDPE processing, effects the different structure of copolymer on the properties and surface properties of the HDPE ontology. The main contents include: (1) design and a new type of low polarity silicon containing monomer was prepared by ethylene (OO7), and the monomer coordination copolymerization reaction, silicon containing ethylene copolymer (E-co-007) on the two. The catalytic system -- rac-EtInd2ZrCl2/MAO and VCl3 (THF) 3/Et2AlCl polymerization behavior, found that the toxic effect of OO7 on silicone macromonomer coordination copolymerization catalyst is much lower than other species. With the OO7 adding amount from 80 Mmol/L increased to 280 mmol/L, E-co-OO7 comonomer insertion rate increases from 1.7 mol% to 5.6 mol%, the weight average molecular weight decreased from 22700 g/mol to 10700 g/mol, the molecular weight distribution index decreased from 2.6 to 1.7. thermal performance study shows that E-co-OO7 co monomer content is high, the glass transition temperature is low (~ -76.1 -64.0 C), crystallization is weak. (2) the low hydrogen containing silicone oil and single terminal double polyethylene (vPE) the hydrosilylation reaction of the first two polydimethylsiloxane -g- polyethylene copolymer (PDMS-g-PE). Low hydrogen containing silicone oil containing hydrogen content is high, the more PE chains were grafted on the molecular. The greater amount of PDMS-g-PE (weight average molecular weight is 69800 ~ 82900g/mol, the molecular weight distribution index ranged from 2.8 to 4), and siloxane content is lower (27 ~ 46wt%). The thermal properties showed that very low glass transition temperature of PDMS-g-PE (-124.5 ~ -118.2 C), and the lower the content of siloxane copolymer And the glass transition temperature is higher, the stronger the crystallization performance. (3) the preparation of a series of different chain length containing siloxane poly siloxane with similar molecular weight (PHSX), by the hydrosilylation reaction of PHSX and vPE, the new -b- polyethylene polyalkylsiloxane -b- polyethylene copolymer synthesized (PE-b-PHSX-b-PE copolymer). The weight average molecular weight is 16100 ~ 18700 g/mol, the molecular weight distribution index was 1.5 ~ 1.7, 21 ~ siloxane content on thermal properties of 48wt%. showed that PE-b-PHSX-b-PE siloxane chain segments longer, the lower the glass transition temperature (-120.5 ~ -89.0 C), crystallization properties study morphology indicated that the increasingly weak. After the operation, after annealing, the copolymer surface and bulk phase morphology showed a lamellar phase separation. (4) studied more than three vinyl siloxane copolymer as the application effect of HDPE composite lubricant. The results showed that adding a small amount (2%, 5% or 10%) vinyl siloxane copolymer The fluidity of HDPE increased, reducing the elastic modulus and tensile strength, the elongation increased, increase the notched impact strength, surface tension, friction coefficient and wear rate decreased. With the longest siloxane chains of the triblock copolymer PE-b-PHSX15-b-PE and has the best lubrication lubrication, the blends (added 5%) melt index (2.53g/10min) was 81% higher than that of pure HDPE, water contact angle (106 degrees) is higher than pure HDPE]8%, friction coefficient (0.047) was lower than pure HDPE 35%, the wear rate (5.2 x 10-3 mm3/Nm) lower than that of the pure HDPE and 53%. commonly used lubricants (silicone masterbatch or polyethylene wax) compared to vinyl siloxane copolymer, and external lubrication, with a full range of superior mechanical properties and thermal stability.

【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：O631

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