【作者】 罗霞；

【导师】 杨军校；

【作者基本信息】 西南科技大学 ， 材料工程（专业学位）， 2020， 硕士

【摘要】 丙烯酸酯-苯乙烯-丙烯腈（Acrylate-Styrene-Acrylonitrile,ASA）是由丙烯酸酯、苯乙烯、丙烯腈为主要的反应试剂,通过乳液聚合合成的核-壳结构的接枝共聚物。核壳结构的ASA通常使用丙烯酸酯与交联剂和接枝剂等作为橡胶核层,当然,具有接枝或交联功能的单体也可以同时用于核层共聚,当核层聚丙烯酸酯反应至一定的程度后,利用反应过程中丙烯酸酯未交联部分残余的双键继续链接苯乙烯（St）与丙烯腈（AN）共聚物形成壳层。丙烯酸酯聚合物抗冲击性能强,耐候性好,苯乙烯成型加工性能优异,丙烯腈耐化学性好,刚性强;通过乳液聚合合成的核-壳结构的ASA,使得三种反应单体的性能得到了有效的结合,具有卓越的电性能、机械性能、耐候性的核-壳结构的ASA在生产生活的各行各业中被广泛运用。研究表明,要想提高ASA的性能,可以在聚合过程加入功能型单体,如在核层可以引入有机硅氧烷,对核进行改性,提高材料韧性;改善材料的耐热性能,可以在壳层的制备中,加入α-甲基苯乙烯,而添加甲基丙烯甲酯则可以增强其光泽度和刚性。基于ASA的优良性能及使用情况,我国对ASA及ASA与聚氯乙烯（PVC）、聚甲基丙烯酸甲酯（PMMA）、聚碳酸酯（PC）、聚酰胺（PA）、聚对苯二甲酸丁二醇酯（PBT）等的合金材料也进行了相关的研究,但大多较为基础,主要研究了ASA的合成方法及改性和共混合金材料的性能。基于对ASA合金材料的基础研究,深入开发高性能、多功能化的ASA将成为研究人员研究的新方向,并具有广阔的应用前景和工业价值。本论文主要采用丙烯酸丁酯（BA）、苯乙烯、丙烯腈为原料,通过乳液聚合工艺、氧化还原引发合成了核壳结构的PBA-ASA三元接枝共聚物,合成的乳液粒径均一稳定且分散性好。通过傅里叶红外光谱分析（FTIR）、动态光散射（DLS）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、差示扫描量热分析（DSC）、热重分析（TG）、力学性能测试等测试方法表征了PBA-ASA胶粉的结构与PBA-ASA/PMMA合金性能。探究了乳化剂的用量、交联剂种类和用量等对合成橡胶核聚丙烯酸丁酯（PBA）乳胶粒子粒径大小的影响,乳胶粒子粒径数值随乳化剂和交联剂的用量的增大而减小;将合成的PBA-ASA核壳接枝共聚物与PMMA按不同比例共混制备的合金做了力学性能测试,结果表明,在PBA-ASA/PMMA体系中,合金冲击强度在PBA-ASA/PMMA为3:7时最佳,最高可达5.5 KJ/m²;PBA-ASA/PMMA合金冲击强度随交联剂的用量的增大先升高后降低。对比交联剂邻苯二甲酸二烯丙酯（DAP）、二丙烯酸己二醇酯、3-（乙氧基）-三羟甲基丙烷三丙烯酸酯（TMP（EO）₃TA）,实验交联剂选择DAP合成的胶粉制备的合金冲击性能最好。用丙烯酸甲酯或甲基丙烯酸甲酯代替接枝壳层单体丙烯腈,合成的胶粉与PMMA共混制得的合金冲击性能大幅降低。为了提升胶粉的抗冲击性能,考虑在丙烯酸酯内核中引入有机硅氧烷进行改性。通过酸催化八甲基环四硅氧烷（D4）、四乙氧基硅烷（TEOS）、γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH-570）开环,在乳液中与丙烯酸酯共聚得到带双键的硅丙种子核乳液,壳层继续接枝苯乙烯-丙烯腈（SAN）合成了一种硅杂的ASA胶粉（Si-ASA）。探讨了乳化剂的种类和用量、KH-570用量、反应合成时间对合金冲击性能的影响。对比PBA-ASA/PMMA合金,Si-ASA/PMMA合金冲击性能明显得到提高,合金冲击性能可以达到8KJ/m²左右。对比采用阴离子乳化剂十二烷基磺酸钠（SDS）、十二烷基苯磺酸钠（SDBS）合成的Si-ASA胶粉与PMMA的合金,SDS作乳化剂时,合金冲击性能会更好。合金的冲击性能随硅烷偶联剂KH-570的量增加,先升高后降低,在KH-570用量为0.02 wt%达到最大值。对比PBA-ASA合成条件,缩短Si-ASA核层和壳层的合成时间,均会使合金的冲击性能降低,且合金表观会出现发雾现象。与PBA-ASA/PMMA合金性能相似,以丙烯酸甲酯或甲基丙烯酸甲酯代替接枝壳层单体丙烯腈,合成的Si-ASA与PMMA制得的合金冲击性能均大幅下降,但仍能达到6KJ/m²,且冲击性能远远优于PBA-ASA/PMMA合金,增韧效果很明显。具有一定的研究意义和开发前景。更多还原

【Abstract】 Acrylate-styrene-acrylonitrile（Acrylate-Styrene-Acrylonitrile,ASA）is a core-shell grafted copolymer synthesized by emulsion polymerization.The rubber core layer is usually prepared from acrylate,crosslinking agent and grafting agent.When the reaction of the polyacrylate core layer reaches a certain level,the double bond on the free acrylate can continually initiate the copolymerization of styrene（St）and acrylonitrile（AN）on core layer to form a shell layer.Acrylic-polymer has strong impact resistance,good weather resistance,styrene-based polymer has excellent molding and processing performance,and acrylonitrile-based polymer has chemical resistance and strong rigidity.Thus,the core-shell structure endowed ASA with combined properties,such as excellent electrical properties,mechanical properties and weather resistance,etc.Sometimes,monomers with functional groups were used for copolymerization to improve the performance of ASA.For example,organosiloxane can be introduced in the core layer to modify the core and improve the toughness;α-methyl styrene can be added in the shell layer and improve the heat resistance,and the addition of methyl methacrylate can enhance its gloss and rigidity.ASA alloy material with polyvinyl chloride（PVC）,polymethyl methacrylate（PMMA）,polycarbonate（PC）,polyamide（PA）,poly(butyl glycol terephthalate（PBT）and their preparation method and properties have been extensively studied.Recently,much effort have been focused on the in-depth development of high-performance,multi-functional ASA with broad application prospects and industrial value.In this paper,the core-shell PBA-ASA ternary graft copolymer was synthesized with butyl acrylate,styrene,and acrylonitrile through redox-initiated emulsion polymerization.The particle size of as-prepared emulsions was uniform and stable.Through Fourier transform Infrared Spectroscopy（FTIR）,Dynamic Light scattering（DLS）,Scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,differential scanning calorimetry（DSC）,thermogravimetric analysis（TG）,and mechanical properties test,the structure of PBA-ASA powder and the properties of PBA-ASA/PMMA alloy were characterized.The influence of the amount of emulsifier,and the type and amount of crosslinker on the particle size of polybutyl acrylate（PBA）rubber was studied.It was found that the size of latex was decreased with the increase of emulsifier and crosslinking agent.The properties of the PBA-ASA core-shell graft copolymer and its alloy prepared by mixing PMMA in different proportions were measured.The best impact strength reached to 5.5KJ/m²with PBA-ASA/PMMA ratio of 3:7.The impact strength of PBA-ASA/PMMA alloy was increased first and then was decreased with the increase of crosslinking agent dosage.Comparedwithdiallylphthalate（DAP）,adiponecyldiacrylate,3-（ethoxy）-trihydroxymethylpropane triacrylate（TMP（EO）₃TA）,the powder synthesized by DAP was selected as the crosslinking agent for the best impact performance of the alloy.The impact properties of the alloy using methyl acrylate and methyl methacrylate instead of acrylonitrile as the graft shell monomer were greatly reduced.In order to improve the impact resistance of rubber powder,organosiloxane was introduced to modify acrylate kernel.Octamethylcyclotetrasiloxane（D4）,tetraethoxysilane（TEOS）,andγ-methacryloxypropyltrimethoxysilane（KH-570）were copolymerized with butyl acrylate to obtain a silicon-acrylic seed core emulsion with double bonds.styrene-acrylonitrile（SAN）was continuously grafted on core layer to synthesize a silicon-hybrid ASA powder（Si-ASA）.The effects of the type and amount of emulsifier,the amount of KH-570,and the reaction time on the impact properties of the alloy were investigated.Compared with the PBA-ASA/PMMA alloy,the impact performance of the Si-ASA/PMMA alloy was obviously improved,and the impact performance of the alloy could reach about 8 KJ/m².Compared with the alloy using Sodium dodecyl sulfonate（SDS）or Sodium dodecyl benzene sulfonate（SDBS）as emulsifier,the alloy prepared from SDS emulsifier exhibited better impact property.The impact performance of the alloy was increased and then decreased with the amount of silane coupling agent KH-570,and reached the maximum value at the amount of 0.02 wt%.The impact performance of the alloy was reduced when shortening the synthesis time of Si-ASA in the core layer or shell layer,and the fogging would appear in the alloy.In consistent with PBA-PMMA alloy,the impact performance of Si-ASA/PMMA alloys was decreased significantly when methyl acrylate or methyl methacrylate rather than acrylonitrile were used as shell monomer.The impact performance of the Si-ASA/PMMA alloys was much higher than PBA-ASA/PMMA alloys,implying a great research significance and development potential of Si-ASA/PMMA alloyes.更多还原