ACR抗冲击改性剂的合成及其在聚乳酸改性中的应用研究

通过对粒子形态及结构设计,合成了以适度交联的聚有机硅橡胶和丙烯酸丁酯共聚物的复合橡胶相为核,以甲基丙烯酸甲酯和甲基丙烯酸缩水甘油酯共聚物为壳,具有核/壳结构的丙烯酸酯类共聚物（ACR）抗冲击改性剂。用红外光谱和透射电子显微镜对其组成和结构进行了表征,并对其在聚乳酸（PLA）中的应用进行了研究。结果表明,当ACR的平均粒径为280 nm时,添加10 %的ACR,PLA/ACR共混物的缺口冲击强度可达39.6 kJ/m2, 雾度小于20 %,熔融塑化时间降低9 min,平衡扭矩提高3.3 N·m,最大扭矩提高2 N·m。     

ACR—g—VC共聚物的合成与性能研究

由两步乳液聚合合成了核－壳结构型ACR胶乳,并进一步通过ACR胶乳存在下的VC悬浮聚合合成ACR－g-VC共聚物,对接枝共聚物的结构和性能进行表征。结果表明：ACR胶乳的存在影响VC悬乳聚合的稳定性,增加分散剂用量能得到颗粒特性较好的共聚树脂;ACR－g-VC共聚物的溶胶聚合度略低于相同聚合温度的均聚PVC,凝胶含量随共聚组成中ACR含量的增加而增加;ACR－g-VC共聚物的塑化时间小于聚合度接近的均聚PVC,而加工转矩大于均聚ACR－g-VC共聚物的冲击强度随ACR含量的增加而增大,且大于ACR含量相当的PVC／ACR共混物。     

ACR核层中交联单体对PC/ACR共混物性能的影响

用丙烯酸丁酯、交联单体和甲基丙烯酸甲酯经乳液聚合和后处理制备了聚丙烯酸丁酯(PBA)/聚甲基丙烯酸甲酯(PMMA)核壳结构的丙烯酸酯树脂(ACR),然后将ACR与聚碳酸酯(PC)共混进行增韧改性。研究了ACR核层中交联单体对PC/ACR共混物力学性能的影响,并用SEM对共混物冲击断面形貌进行了研究。结果表明:随着ACR核层中交联单体含量的增加,PC/ACR共混物的缺口冲击强度呈现先增加后降低的趋势,拉伸强度和弯曲强度变化很小。当交联单体B含量为10%时,PC/ACR共混物的冲击强度达到最大为50.4 kJ/m2,约是纯PC冲击强度的5倍。     

核-壳结构冲击改性剂ACR合成技术研究

采用种子乳液聚合工艺合成了核-壳结构冲击改性剂ACR,重点考察了ACR胶乳粒径及ACR/PVC共混物性能的影响因素,对ACR胶乳粒径及其分布、胶乳粒子形态结构及ACR树脂的结构和性能进行了表征和测试。     

ACR增韧PBT/PC合金的研究

研究了“核-壳”结构的ACR对PBT/PC(质量比80/20)合金的力学性能和耐热性的影响。结果表明:随着ACR用量增加,共混物的缺口冲击强度不断增大,而拉伸强度、弯曲强度、维卡耐热度降低。当ACR的加入量为5份时,缺口冲击强度提高1倍,当ACR的加入量为30份时,缺口冲击强度约为纯PBT/PC合金的5倍。从增韧效果来看,FM50略好于KM355。     

抗冲ACR树脂的合成及其性能评价

采用种子乳液聚合法,以丙烯酸丁酯为核层单体、甲基丙烯酸甲酯为壳层单体、甲基丙烯酸烯丙酯为交联剂制备了抗冲ACR树脂。考察了不同加料方式对ACR乳液粒径及对PVC冲击性能的影响,结果表明:连续滴加方式可实现乳液粒径的稳定控制,并能得到性能优异的抗冲ACR树脂。     

聚氯乙烯增韧改性剂的合成及共混改性研究

采用传统的乳液接枝聚合方法合成了以交联聚丙烯酸酯弹性体为核，聚氯乙烯（PVC）直接为壳层的新型聚氯乙烯复合改性剂，用于通用聚氯乙烯的增韧改性。通过粒径分析仪、透射电镜、动态力学分析等手段对复合粒子及其共混改性PVC材料进行了表征与测试。结果表明复合粒子具有核壳结构，粒径分布较窄；动态力学分析显示；改性剂的加入有效地改善了改性剂与PVC基体问的相容性；当改性剂加入量为6％（核壳质量比为50／50）时，改性PVC材料的缺口冲击强度为纯PVC的5倍。     

PC/PBT合金增韧改性的研究

研究了“核-壳”结构的丙烯酸酯类(ACR)抗冲改性剂对PC／PBT(80／20)合金力学性能和耐热性的影响；并用扫描电子显微镜对共混物的微观形态结构进行了分析。结果表明：随ACR抗冲改性剂的增加，共混物的冲击强度先增后降，当ACR的用量为15份时，出现最大值；同时共混物的拉伸强度和维卡软化温度都降低。     

正交试验法优化ACR增韧PLA的制备工艺

采用乳液聚合法制备了一系列核壳型增韧改性剂ACR并用于聚乳酸(PLA)的增韧。利用L16(45)正交试验设计方法,研究了ACR粒子的核壳比、粒径、用量以及交联剂用量对共混体系结构和性能的影响。结果得出增韧PLA的最佳工艺条件为:ACR核壳比75/25,粒径约185.0 nm,用量20%,交联剂用量0.5%。此时PLA/ACR共混物的冲击强度为29.128 kJ/m~2,约为纯PLA的11倍。极差分析结果表明,ACR用量和核壳比是影响增韧效果的主要因素。     

ACR中壳层PMMA相对分子质量对PVC／ACR共混物性能的影响

采用种子乳液法制备了核壳型聚丙烯酸酯(ACR),并分别采用十二烷基硫醇和正辛基硫醇作为链转移剂对 ACR壳层的聚甲基丙烯酸甲酯(PMMA)进行相对分子质量调节,并用于PVC共混改性。黏度法对PMMA的相对分子质量测定表明,正辛基硫醇的相对分子质量调节能力较强。采用差示扫描量热分析测定PMMA的玻璃化转变温度(Tg),并对共混树脂进行动态力学性能测试。当ACR壳层PMMA平均相对分子质量低于12×104时,PVC/ACR 共混树脂的缺口冲击强度大大提高。与纯PVC相比,共混树脂的Tg均略有提高,其增量随ACR壳层PMMA平均相对分子质量的降低而减小。动态力学性能测试结果表明,ACR壳层聚合物平均相对分子质量越低,共混物分子链段运动活化能提高越少。     

以PVC为外壳层的ACR抗冲改性剂的合成及其对PVC的增韧作用

以聚丙烯酸丁酯(PBA)为内核,通过种子乳液聚合制备了分别以聚甲基丙烯酸甲酯(PMMA)、聚氯乙烯(PVC)、PMMA/PVC为壳层的纯丙烯酸酯(ACR)和PVC改性ACR乳液.扫描电镜观察发现,纯ACR乳胶粒子具有明显的核-壳结构,进一步包覆PVC后形成疏松外层.考察了不同结构ACR与PVC共混物的相态结构、抗冲性能和断面形貌,发现用PVC部分或完全替代PMMA壳层的改性ACR在PVC基体分散良好,具有与纯ACR相当的增韧PVC作用,冲击断面呈现典型的韧性断裂特征.     

Effects of core‐shell acrylate particles on impact properties of chlorinated polyethylene/polyvinyl chloride blends

The impact properties of core‐shell acrylate (CS‐ACR)/chlorinated polyethylene (CPE)/poly(vinyl chloride) (PVC) blends under different temperatures were investigated. The fracture surface morphologies of the blends were observed by scanning electron microscopy (SEM). The results show that there exists significant synergistic effect between CS‐ACR particles and CPE in toughening PVC, and the impact properties of the blends generally correlate well with SEM morphologies. Besides, with increasing CS‐ACR content, ductile–brittle transition point of the ternary blends remarkably shifts to a lower temperature. Dynamic mechanical analysis exhibited that intensity and area of low‐temperature tan δ peaks of the CPE/PVC blends increase obviously after the addition of CS‐ACR particles, which to some extent are just in line with the changes in impact strength and ductile–brittle transition point of the blends. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

一种新型交联剂对ACR增韧PVC的影响

采用二甲基丙烯酸乙二醇酯（EGDMA）作为一种新型交联剂,以种子乳液聚合方法合成了一系列不同交联剂含量的丙烯酸酯类核壳增韧改性剂（ACR）,用于对聚氯乙烯（PVC）树脂的增韧改性研究。通过改变交联剂的含量,测试了ACR的交联度、接枝度、接枝效率和玻璃化转变温度（Tg）。研究了ACR/PVC共混物的力学性能与交联剂含量之间的关系。数据显示：当交联剂含量增加时,ACR的交联度、接枝度、接枝效率和玻璃化转变温度都得到了升高。当交联剂含量为0.4%,ACR/PVC的质量比为8/100时,ACR/PVC共混物发生了脆韧转变,冲击强度为1145J/m,是纯PVC的39倍。     

Toughening of poly(butylene terephthalate) by polyacrylic impact modifier

Core–shell structured polyacrylic (named ACR) impact modifiers consisting of a rubbery poly(n-butyl acrylate) (BA) core and a rigid poly(methyl methacrylate) shell with a size of about 310 nm were prepared by seed emulsion polymerization. The ACR modifiers with different core–shell weight ratios (85:15; 80:20; 75:25; 70:30) were used to modify the toughness of poly(butylene terephthalate) (PBT) by melt blending. It was found that the polymerization had a very high instantaneous conversion (>90 %) and overall conversion (98 %). The ACR latexes had an obvious core–shell structure confirmed by transmission electron microscope. The mechanical properties of the PBT/ACR blends were evaluated, and scanning electron microscope (SEM) was used to observe the fractured morphology. Dynamic mechanical analysis and differential scanning calorimeter were used to study the molecular movement and crystallization behaviors of PBT/ACR blends. The results indicated that with an appropriate value of the core–shell weight ratio, poly(BA) could disperse well in the matrix and the brittle–ductile transition point could emerge. As a result, the notch impact strength of PBT/ACR blends with a core–shell weight ratio of 80:20 was 6.7 times greater than that of pure PBT, and the mechanical properties agreed well with the SEM observation.     

The surface modification of nanosilica,preparation of nanosilica/acrylic core‐shell composite latex,and its application in toughening PVC matrix

The properties and morphology of nanosilica modified with silane coupling agent, methacryloxypropyltrimethoxysilane (MPS), were characterized by fourier transform infrared, zeta potentials, thermogravimetric analysis, and transmission electron microscopy. The results showed that the grafting ratio of MPS on the surface of nanosilica increased with the MPS content. MPS‐silica/PBA/PMMA core‐shell latexes (MPS‐Si/ACR) were prepared by seeded emulsion polymerization. Then they were used to mix with PVC resin. The outer layer (PMMA) enhanced the dispersibility of MPS‐Si/ACR in the PVC matrix by increasing the interfacial interaction of these composite particles with PVC. The notched impact strengths of the blends were influenced by the weight ratio of MPS to silica, the concentration of emulsifier (SDS), and the MPS‐Si/ACR content. The relationships between the mechanical properties and the core‐shell composite structures were elaborated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

CPVC/PVC/ACR三元共混材料的研究

研究了CPVC／PVC/ACR三元共混材料的物理力学性能。结果表明，共混材料的维卡软化温度和拉伸屈服强度随CPVC用量的增加而增加；当ACR用量为6-8份时，可明显改善共混材料的抗冲性能。     

聚丙烯酸酯原位乳液聚合包覆SiO2的研究

用经甲基丙烯酰氧基丙基三乙氧基硅烷（MAPS）处理过的纳米SiO2作种子，进行聚丙烯酸酯（ACR）的原位乳液聚合，制成了MAPS－SiO2/ACR复合物；探讨了种子乳液聚合的过程，分析了包覆机理，讨论了SiO2的用量对聚合反应速率及残渣率的影响，结果表明：在以纳米SiO2为种子的ACR乳液聚合中，单体的转化率及聚合反应速率随SiO2用量的增加而下降；当SiO2的用量为10％时，复合物与聚氯乙烯共混后，其拉伸强度和冲击强度最高。     

Preparation and characterization of nano‐CaCO3 encapsulated with polyacrylic and its application in PVC toughness

The properties and morphology of nano‐calcium carbonate (nano‐CaCO₃) modified with the titanate coupling agent isopropyl trioleoyl titanate (IPTT) were characterized by Fourier transform infrared, thermogravimetric analyses, surface tension, and transmission electron microscopy. The results showed that the grafting ratio of IPTT on the surface of nano‐CaCO₃ (IPTT‐Ca) increased with IPTT content. IPTT‐Ca/PBA/PMMA (IPTT‐Ca/ACR, PBA/PMMA core‐shell polymer, referred to ACR) latexes were prepared by seeded emulsion polymerization. They were then used to mix with PVC resin. The outer layer (PMMA) enhanced the dispensability of IPTT‐Ca/ACR in the PVC matrix by increasing the interfacial interaction of these composite particles with PVC. The notched impact strengths of the blends were influenced by the weight ratio of IPTT‐Ca to BA/MMA monomers, the weight ratio of BA/MMA. The relationships between the mechanical properties and the core‐shell composite structures were elaborated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010