悬浮接枝共聚合成POE-g-MAS及其对SAN树脂的增韧作用

合成了乙烯-辛烯共聚物(POE)和甲基丙烯酸甲醋(MMA)-丙烯腈(SAN)-苯乙烯(St)的接枝共聚物(POE-g-MAS)。研究了单体比率、POE/单体比率和引发剂浓度等因素对接枝共聚合反应的影响。聚合产物用丙酮抽提得到接枝共聚物POE-g-MAS,傅里叶变换红外光谱分析证明MMA-AN-St已经接枝在POE分子链上。用POE-g-MAS与Stet树脂共混制备了具有高抗冲性能的POE-g-SAN/SAN共混物,并用扫描电镜观察共混物的冲击断面,探讨了其增韧机理。     

POE-g-MAS增韧SAN树脂及其相容性

合成了乙烯-辛烯共聚物(POE)和甲基丙烯酸甲酯-丙烯腈-苯乙烯的接枝共聚物(POE-g-MAS).用POE-g-MAS与苯乙烯-丙烯腈共聚物(SAN)树脂共混制备了具有高抗冲击性能的SAN,POE-g-MAS共混物,研究了接枝链极性、接枝率和POE含量对共混物冲击性能的影响,当m(St)/m(MMA)/m(An)为10:70:20,接枝率为45.1%,w(POE)为25%时,共混物的缺口冲击强度达到56.1kJ/m2.用扫描电子显微镜和差示扫描量热仪研究表明,POE-g-MAS与SAN树脂有良好的相容性.     

微波辅助POE-g-AN的制备与耐油性

采用微波法制备乙烯-辛烯共聚物(POE)接枝丙烯腈(AN),探究了接枝的工艺,并对POE-g-AN的耐油性、电性能进行了对比分析.结果 表明,制备工艺是微波温度85℃、微波时间60 min、溶液浓度12.5％,当POE、AN、苯乙烯(St)和过氧化苯甲酰(BPO)的质量比为100∶100∶4∶0.2时,POE-g-AN...     

SAN共聚物中AN含量对PVC/ABS/DOP共混物结构与性能的影响

采用半连续乳液聚合技术将聚苯乙烯(St)和丙烯腈(AN)接枝到聚丁二烯(PB)乳胶粒子上,通过改变共聚单体的投料比(St/AN)合成了一系列不同AN含量的丙烯腈-丁二烯-苯乙烯共聚物(ABS)接枝共聚物,将其与聚氯乙烯(PVC)和增塑剂邻苯二甲酸二辛酯(DOP)熔融共混制得PVC/ABS/DOP(40/40/20)共混物。研究了共混物的热挺型性、微观形态结构和动态力学性能。结果发现,该共混物为双相连续结构,随着接枝SAN共聚物中AN含量的增加,由于DOP小分子与SAN共聚物的相互作用逐渐减弱,导致了SAN相的Tg和共混物的储能模量不断提高,改善了共混物的热挺型性,阐明了PVC/ABS/DOP共混物热挺型性的科学本质。     

悬浮法PEB-g-SAN的合成及其对SAN树脂的增韧作用

以(乙烯/1丁-烯)共聚物(PEB)、苯乙烯(St)和丙烯腈(AN)为原料,采用悬浮接枝共聚法合成了(苯乙烯/丙烯腈)共聚物(SAN)接枝PEB(PEB-g-SAN),用其与SAN熔融共混制备了冲击性能优异的增韧塑料AEBS。研究了反应条件对单体转化率(CR)、接枝率(GR)、接枝效率(GE)及AEBS冲击性能的影响。结果表明,在适宜的聚合条件下,PEB/St-SAN悬浮接枝体系具有较高的CR、GE和GR,分别可达94.8%、49.3%和38.2%。当PEB质量分数为25%时,AEBS的缺口冲击强度高达42.8 kJ/m2,约为纯SAN(1.2 kJ/m2)的35倍。扫描电子显微镜分析表明,增韧机理以剪切屈服为主。动态机械分析表明,在PEB-g-SAN接枝反应中,当PEB质量分数为55%、AN为35%时,其增韧的AEBS的两个tanδ峰向内靠拢程度最大,SAN与PEB-g-SAN的相容性最好。     

丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物AES的合成

用溶液聚合法合成了丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物（AES）,研究了接枝聚合反应的影响因素,并进行了红外光谱表征。结果表明,三元乙丙橡胶（EPDM）已接枝上丙烯腈（AN）和苯乙烯（St）的共聚物（SAN）支链,即EPDM与AN及St发生了接枝共聚合反应。     

溶液接枝法合成EPDM-g-SAN

以过氧化二苯甲酰(BPO)为引发剂，正庚烷／环己酮为溶剂，用溶液接枝法合成了高胶含量的苯乙烯(St)-三元乙丙橡胶(EPDM)-丙烯腈(AN)接枝共聚物(EPDM-g-SAN)。研究了反应温度、引发剂浓度、EPDM含量、混合溶剂的配比以及反应时间对接枝共聚合反应的影响。FTIR分析证实EPDM已接枝上SAN支链。实验证明，接枝共聚物对SAN树脂具有良好的增韧效果。     

POE/SAN的原位增容

通过扭矩测定,傅里叶变换红外光谱、差示扫描量热法分析等方法研究了苯乙烯-丙烯腈共聚物(SAN)与聚烯烃弹性体(POE)大分子间的Friedel-Crafts烷基化反应。结果表明:适量无水AlCl3可以引发SAN与POE发生Friedel-Crafts烷基化反应,生成的POE-g-SAN接枝共聚物起到了原位增容POE/SAN共混物的作用,提高了其力学性能;当m(POE)/m(SAN)为60.0∶40.0,反应温度为180℃,AlCl3用量为0.4 phr时,POE/POE-g-SAN/SAN共混物性能较好;进一步提高AlCl3用量,SAN分子结构中侧链氰基与铝离子络合作用增强,导致SAN分散相聚集,POE/POE-g-SAN/SAN共混物刚性下降。     

悬浮接枝共聚合成POE-g-MAS及其表征

用悬浮接枝法合成了乙烯-辛烯共聚物（POE）和甲基丙烯酸甲酯（MMA）-丙烯腈（AN）-苯乙烯（St）的接枝共聚物（POE-g-MAS）。研究了单体比率、POE／单体的比率、引发剂浓度和反应时间等因素对接枝共聚合反应的影响。从聚合产物中用丙酮抽提得到接枝共聚物POE-g-MAS,并用傅立叶变换红外光谱（FTIR）和差示扫描量热法（DSC）对POE-g-MAS进行了分析。实验证明MMA-AN-St已经接枝在POE分子链上。接枝链MAS在一定程度上影响了POE的结晶相,降低了POE的熔融温度和熔融热。     

EPDM-g-MAN的合成及AEMS的冲击性能研究

用(乙烯/丙烯/二烯)共聚物(EPDM)与甲基丙烯酸甲酯(MMA)、丙烯腈(AN)进行溶液接枝共聚合成了(EPDM/MMA/AN)接枝共聚物(EPDM-g-MAN),并将其与(苯乙烯/丙烯腈)共聚物(SAN)共混制得高抗冲耐老化黄变性能优异的EPDM-g-MAN/SAN共混物(AEMS).研究了AN用量对不同EPDM-g-MAN接枝体系单体转化率(CR)、接枝率(GR)、接枝效率(GE)及AEMS缺口冲击强度的影响.结果发现,随着AN用量的增加,EPDM-g-MAN的CR逐渐下降;GR、GE在AN质量分数为5%时出现最大值;AEMS的缺口冲击强度均在AN质量分数为10%时出现最大值,为61.0 kJ/m2;EPDM相以条状形态构成的近连续相结构存在,径向尺寸较小的EPDM条形结构能诱发SAN基体剪切屈服,径向尺寸较大的EPDM条形结构仅能诱发基体空穴化.     

Block copolymer nanoshells

With the help of cell dynamics simulation we investigate morphology of thin block copolymer film around a nanoparticle. The obtained structures include: parallel, perpendicular, mixed and perforated lamellae, parallel and perpendicular cylinders and spheres. Analogy and difference with planar films are discussed. Our simulation suggests that novel porous nanocontainers can be formed by the coating of a sacrificial nano-bead by a block copolymer layer with a well controlled nanostructure.     

Diblock copolymer healing

The issue of self-healing materials is of paramount importance due to its intrinsic scientific value, as well as potential applications in a wide variety of fields, such as manufacturing, medicine, and electronics. We have investigated the behavior of poly(styrene-b-methylmethacrylate) diblock copolymer, following deformation performed by a silicon atomic force microscopy tip. We observed the changes in the polymer as it was subsequently heated in situ, and found how diblock “scars” can heal. These observations give important guidance to efforts that seek to create nanostructures using these methods, while also revealing fundamental insights into the mechanisms of polymer repair on the nanoscale.     

Block copolymer deformation

The deformation behavior of block copolymers is examined. Interdomain bridges, loops, cilia and floating chains in spherical, cylindrical and lamellar domain morphologies are considered. In the theoretical model, which is analogous to the “three-chain” model in classical rubber elasticity theory, interdomain chains are confined between pairs of infinite, parallel impenetrable walls constructed at the surfaces of nearest neighbor domains. The domains are taken as undeformable. The quantities which are calculated are: the Young's modulus; the partial molar elastic free energy of swelling; and the stress-strain relation for simple extension.     

Toughening isotactic polypropylene and propylene-ethylene block copolymer with styrene-ethylene butylene-styrene triblock copolymer

Dynamic mechanical properties, low-temperature impact behavior, flexural modulus and heat distortion temperature (HDT) of isotactic polypropylene (i-PP) and propylene-ethylene block copolymer (Co-PP) toughened with styrene-ethylene butylene-styrene triblock copolymer (SEBS), at blending ratios of 0–30 phr, were studied and compared. A scanning electron microscopic morphology study of the impact-fractured surfaces demonstrated the changes in fracture mechanisms at various temperatures and SEBS contents. SEBS remarkably improves the impact endurance in the lower-temperature range when blended with Co-PP in comparison with i-PP, due to the increased compatibility in the interface between SEBS particles and the Co-PP matrix.     

Water-based epoxy-acrylic graft copolymer

High molecular weight epoxy resins have been grafted with styrene−methacrylic acid monomers; the epoxy-g-(styrene-methacrylic acid) copolymer was water-reducible when neutralized with a base. Characterization of graft sites in the epoxy-g-acrylic copolymer by ¹³C NMR spectroscopy is described. Grafting takes place at the aliphatic carbons of the epoxy resin. The rationale for this behavior is presented.     

Premix copolymer cement materials

Studies to determine the influence of mixtures of monomers (and subsequently copolymers) on the behaviour of premix copolymer cement materials are described in this paper. Five system viz styreneacrylonitrile, styrene-vinyl acetate, methyl methacrylate - vinyl acetate, butyl methacrylate - methyl methacrylate and butyl acrylate - methyl methcrylate, were investigated. Setting time and hydration studies were carried out on premix cement pastes while compressive strength tests were carried out on premix mortars, to determine the influence of monomer volume, surfactants and polymerisation method. The results indicated, as has most of the work on premix systems, that the influence of the copolymers was to increase setting time, decrease the degree of hydration as measured by percentage of chemically combined water and decrease strength relative to that of specimens continuously moist cured.     

Polyacrylamide-grafted dextrine copolymer coatings

Polyacrylamide (PAM)-grafted dextrine (DEX) copolymers were prepared by heating a film-forming precursor solution consisting of PAM, corn starch-derived DEX, cerium (IV) nitrate hexahydrate, and water, at 150° or 200°C; these solutions were applied as water-based primer coating systems to aluminum (Al) substrates. Grafting PAM on the DEX not only inhibited the fragmentation of DEX structures caused by oxidation at 200°C in air, but also aided in fabricating coating films that were less susceptible to moisture and minimized the rate of permeation of electrolyte species through the film layers. In addition, the grafted DEX coating films favorably reacted with the Al substrate to form Al-O bonds at interfaces. Consequently, Al panels coated with a highly grafted DEX copolymer had a salt-spray resistance of 600 hr. Energy Efficiency and Conservation Division., Dept. of Applied Science, Upton, NY 11973. This work was performed under the auspices of the U.S. Department of Energy, Washington, D.C. under Contract No. DE-AC02-76CH0016, and supported by the U.S. Army Research Office Program MIPR-7HDOEAR040.     

ACR接枝VC共聚树脂的研究

介绍了ACR-g-VC树脂的制备方法,研究了ACR-g-VC树脂的合成工艺及增韧机制。ACR-g-VC树脂是一种冲击韧性高、综合性能优良的改性PVC专用树脂,具有广阔的发展前景。     

三元共聚对位芳纶的聚合

研究了对苯二胺与对苯二酰氯在N-甲基吡咯烷酮/氯化钙体系中加入3,4’-二氨基二苯醚为第三单体的三元共聚反应。考察反应时间、反应温度、第三单体用量、单体浓度和CaCl_2用量对共聚物对数粘度的影响。结果表明,在N-甲基吡咯烷酮/氯化钙溶剂体系中,单体浓度为(0. 35～0. 40) mol·L^(-1),单体物质的量分数为25%,首先将温度设定为(-10～-5)℃,待溶液黏稠时将温度升高到(75～80)℃,时间(60～80) min,CaCl_2与-2NH_2物质的量比0. 4～0. 6时,可获得高比浓对数粘度的聚合物。