【作者】 王林；

【导师】 何慧；

【作者基本信息】 华南理工大学 ， 材料加工工程， 2020， 博士

【摘要】 通过物理或化学改性的方法,赋予已有聚合物材料新的性能与功能,是目前高分子材料的发展方向之一。其中,聚合物材料的增韧改性是一个重要方面。与刚性粒子、橡胶弹性体和热塑性弹性体相比,核壳聚合物将弹性体与刚性粒子的优点结合起来,可以获得“刚韧并存”的高性能材料。核壳有机硅改性剂具有优异的低温韧性,并且兼具良好的耐紫外老化性能和耐热性等优点,不但可以在提高塑料韧性的同时保持其刚性,而且可以利用有机硅的特殊性赋予材料特有的性能,获得性能优良的改性塑料。本论文采用乳液聚合的工艺,制备了聚丙烯酸酯为壳、有机硅为核的核壳结构有机硅改性剂,研究了有机硅改性剂在低噪音丙烯腈-丁二烯-苯乙烯共聚物（ABS）以及免喷涂聚碳酸酯（PC）材料方面的新应用,通过优化其结构,引入特殊耐候基团,获得具有特殊性能的改性剂,并将其应用于制备耐候高韧性PC材料和耐候阻燃聚氯乙烯（PVC）木塑复合材料,系统研究了核壳有机硅改性剂在不同塑料中的应用,建立起有机硅改性剂结构与性能的关系,扩展有机硅改性剂的应用,为开发新型的有机硅改性剂产品及改性塑料提供方案和思路。论文的主要研究工作包括以下几个方面:（1）以有机硅八甲基环四硅氧烷（D4）、γ-甲基丙烯酰氧基丙基三甲氧基硅烷（KH-570）为核层单体,丙烯酸丁酯（BA）、甲基丙烯酸甲酯（MMA）和丙烯酸（AA）为壳层单体,采用核壳乳液聚合工艺,制备具有核壳结构的有机硅-丙烯酸酯聚合物乳液（poly（D4-MMA-BA））。优化合成工艺条件,研究有机硅单体比例和核壳单体比例对单体转化率、乳液粒径、形态、凝胶率、成膜性以及韧性的影响,并采用傅里叶红外光谱（FTIR）、动态光散射粒径仪（DLS）和透射电镜（TEM）等进行表征。红外光谱分析表明获得了目标产物。当D4与KH-570的比例为41.5:3.5,核层单体与壳层单体的比例为5:4时,所制得的乳液转化率高于98%,凝胶率低于0.5%,且乳液具有良好的成膜性和韧性;热失重（TG）结果显示,poly（D4-MMA-BA）具有良好的耐热性能,起始热分解温度较高（>300℃）,透射电镜显示所制备的乳胶粒子具有核壳结构,粒径约为150nm。（2）采用喷雾干燥工艺,制备核壳结构的有机硅改性剂,以核壳有机硅-丙烯酸酯共聚物、硅酮树脂、聚乙烯蜡和乙撑双硬脂酰胺作为改性剂,制备了低噪音ABS材料。通过摩擦系数测试仪器和自主搭建设计的噪音测试方法,研究了润滑剂种类和用量对ABS材料摩擦噪音的影响。与其他改性剂相比,聚乙烯蜡可以提高材料的表面摩擦性能,减小动静摩擦系数差△F,减缓粘-滑现象的产生,改善摩擦噪音。当聚乙烯蜡用量为4%时,其摩擦噪音仅有58d B。这是因为聚乙烯蜡润滑剂会迁移到材料表面形成一层低表面能物质,不仅降低了材料的表面张力,还使得ABS的动、静摩擦系数以及△F下降,防止材料表面出现粘-滑现象,从而降低摩擦噪音。Poly（D4-MMA-BA）改性剂的引入可以有效提高ABS的韧性和热稳定性,但是会降低其拉伸强度。同时,poly（D4-MMA-BA）改性剂还可以降低材料表面的摩擦系数,提高其抗磨损性能,降低摩擦噪音,但对摩擦力变化值△F的降低有限。采用摩擦测试仪、噪音测试仪、FTIR和扫描电镜（SEM）等对材料进行表征测试,探究摩擦噪音的产生机理和控制的关键因素。研究结果证明,ABS材料摩擦噪音主要是由粘-滑现象产生的,相对滑动时产生的噪音与两制件发生相对滑动时的摩擦力变化值△F有明显的相关性,降低△F可以降低摩擦产生的噪音。（3）以铝银浆为金属光泽材料,核壳有机硅乳液作为包覆材料,采用喷雾干燥工艺,通过优化工艺条件,制备了有机硅包覆铝银浆的铝粉微球,并将得到的铝粉微球用于制备具有金属光泽的免喷涂PC材料,解决免喷涂材料低温韧性差和流痕问题。研究了铝粉微球在PC中的分散情况及其用量对免喷涂PC材料力学性能、外观流痕、热稳定性以及熔体流动性等的影响,采用TG、差示扫描量热仪（DSC）、SEM和元素分析（EDS）等进行表征。研究结果显示,采用喷雾干燥工艺,有机硅-丙烯酸酯聚合物发生了固化反应,并成功包覆了水性铝粉,形成了微球状或片状结构。包覆后的铝粉微球能够大幅度提高PC的冲击韧性,尤其是材料的低温冲击强度。与PC/Al材料相比,PC/包覆铝粉微球材料的常温冲击性能提升了47.2%,低温冲击性能提高了48.8%。对铝粉进行包覆后能够明显降低铝粉的片状结构所带来的取向流动,从而改善聚合物表面的熔接线与流痕。（4）通过2-（2’-羟基-5’-甲基苯基）苯并三唑（UV-P）与丙烯酰氯（AC）的酯化反应,制备具有抗紫外基团和双键的2-（2’-丙酰氧基-5’-甲基苯基）苯并三唑（AMB）功能性单体,将其引入到乳液聚合体系中,采用喷雾干燥工艺,合成具有耐候基团的功能化核壳有机硅改性剂poly（D4-MMA-BA-AMB）,并将其添加到PC中,制备高韧性耐候PC材料。系统研究AMB用量对有机硅乳液聚合稳定性和粒径的影响,分析了AMB的老化机理,探讨耐候有机硅改性剂对PC力学性能以及耐老化性能的影响,并采用FTIR、核磁（¹H-NMR）、TG、TEM、DLS和紫外吸收仪进行表征。结果表明,成功制备了功能化AMB单体。AMB通过断链反应产生苯并三唑（UV-P）,因此具有良好的紫外吸收作用。采用乳液聚合的方法,将AMB与有机硅和丙烯酸酯单体共聚,成功的制备了具有核壳结构的改性剂poly（D4-MMA-BA-AMB）。AMB的引入会降低体系聚合的稳定性,但有助于提高改性剂的热稳定性,所制备的含AMB的有机硅改性剂具有很强的紫外吸收能力。有机硅改性剂的引入会降低PC的拉伸强度,但可以大幅度提高材料的低温缺口冲击强度,同时改善紫外光照后PC产品的韧性和黄变性能。与纯有机硅改性剂相比,含有AMB基团改性剂的PC具有更好的抗紫外效果,经过1000h的紫外光辐照,PC/poly（D4-MMA-BA-AMB）在拉伸强度以及冲击强度（常温、低温）等方面都有较高的保持率,且色差变化较小。此外,与直接添加poly（D4-MMA-BA）和UV-P的PC混合物相比,PC/poly（D4-MMA-BA-AMB）在水煮后具有更好的耐老化性能。（5）将核壳有机硅改性剂poly（D4-MMA-BA-AMB）添加到PVC木塑复合材料中,以改善木塑PVC材料的耐候性、阻燃性和韧性,考察了有机硅改性剂对PVC制品的阻燃性能、力学性能及抗老化性能的影响,采用锥形量热仪、光学显微镜、色差测试仪、老化测试箱等对制品进行表征。结果表明,改性剂poly（D4-MMA-BA-AMB）的引入可提高PVC木塑复合材料（PVC-WPC）的缺口冲击强度,且增韧效果优于其他有机硅改性剂产品。通过调节白木粉、改性剂和三氧化钼（Mo O₃）的配比可以获得性能优良的阻燃耐候PVC-WPC材料,其中最优配比为:白木粉5份,有机硅改性剂2.5份,Mo O₃ 1.5份。改性剂poly（D4-MMA-BA-AMB）和Mo O₃复配可以降低PVC-WPC烟释放及热释放速率,提高残炭率,形成致密的碳层,显著地提升材料的阻燃性能。改性剂的引入还可以提升制品的耐候性能,添加量在3.5%时,制品即可表现出优异的耐候性,在1000小时的加速老化后外观无明显色差变化。Poly（D4-MMA-BA-AMB）还可以提升PVC-WPC制品挤出过程中的熔体粘度,优化发泡工艺,当其添加量为2.5%时,制品呈现出最优的力学性能及泡孔尺寸。更多还原

【Abstract】 Recently,the polymer materials with functional performance by physical or chemical modification method have been one of the development directions.Among them,the toughening modification of polymer materials is an important aspect.Compared with common modifiers of the rigid particles,rubber elastomer and thermoplastic elastomer,the core-shell polymer is suitable for the polymer toughening as it possesses the advantages of other modifiers and can effectively increase the toughness of the polymer while has little effects on the strength.Therefore,the material with high performance can be obtained.The core-shell organic silicon modifier has excellent low-temperature toughness,good ultraviolet aging resistance,heat resistance,and not only improves the toughness of the plastic while maintain its rigidity,but also endows the material with special properties,which is beneficial for the performance improvement of modified plastics.In this work,the core-shell organic silicon modifier with organic silicon core and polyacrylate shell was successfully synthesized by the emulsion polymerization,it showed special properties when incorporating the weather resistance groups by adjusting the polymer structure.The obtained core-shell organic silicon modifiers were applied to the preparation of weather resistance of polycarbonate（PC）material,low noise of acrylonitrile-butadiene-styrene copolymer（ABS）material,free-spraying of PC composite and flame-retardant wood plastic of polyvinyl chloride（PVC）material.Effects of the structure of the core-shell organic silicon modifier on the plastics properties were systematical studies.Meanwhile,the relationship between structure and performance of the organic silicon modifier was also established.The work aims at extending the applications of organic silicon modifier,and providing solutions and ideas for the development of new type of organic silicon products and modified plastics.The research contents and results are listed as following:（1）The core-shell organic silicon and acrylate polymer（poly（D4-MMA-BA））emulsion was successfully synthesized by the core-shell emulsion polymerization using octamethyl cyclotetrasiloxane（D4）andγ-methacryloxypropyl trimethoxysilane（KH-570）as core monomers,and butylacrylate（BA）,methyl methacrylate（MMA）and acrylic acid（AA）as shell monomers.By the optimization of the technological conditions,effects of the proportion of organic silicon monomer and core-shell monomer ratio on the monomer conversion,latex particle size,morphology,gel rate,film-forming and toughness properties were investigated,and were characterized by the Fourier infrared spectrum（FTIR）,dynamic light scattering instrument（DLS）and transmission electron microscopy（TEM）.FTIR showed that the target product was successfully synthesized.When the mass ratio of the D4 to KH-570 and core monomers to the shell monomers were 41.5/3.5 and 5/4,respectively,the obtained poly（D4-MMA-BA）possessed monomer conversion higher than 98%and gel rate lower than 0.5%.Meanwhile,the poly（D4-MMA-BA）showed good film-forming property and toughness.Thermo-gravimetric（TG）indicated that the poly（D4-MMA-BA）had good heat resistance with a high initial decomposition temperature（>300℃）.TEM showed that the prepared latex particles had core-shell structure with particle size of about 150 nm.（2）The core-shell modifier was prepared using spray drying process.The obtained poly（D4-MMA-BA）modifier,silicone lubricant,polyethylene wax and ethylene bis stearamide were used as modifiers for the preparation of the low noise ABS material.Effects of the lubricants on the friction noise of the ABS material were studied based on the friction coefficient tester and a self-designed noise tester.Compared with other lubricants,the polyethylene wax could improve the friction performance of the surface and reduced the△F,thereby reducing stick-slip phenomenon and friction noise.When the polyethylene wax content was 4%,the friction noise of the material was only 58 d B.It was because that the lubricant of polyethylene wax would migrate to the surface to form a layer of low surface energy material,which not only reduced the surface tension of the material,but also made the dynamic and static friction coefficient and△F of the ABS decreased.This would prevent the occurrence of the stick-sliding phenomenon,which improve the friction noise of the material.The introduction of the poly（D4-MMA-BA）modifier could effectively improve the toughness and thermal stability of ABS,but had negative effects on the tensile strength.Meanwhile,the poly（D4-MMA-BA）modifier could reduce the friction coefficient of material,improve the wear resistance and lower the friction noise.However,it had limited effects on the improvement of the△F.The materials were then tested and characterized by the friction tester,noise tester,FTIR and scanning electron microscope（SEM）to study the key factors and mechanism of friction noise.Results showed that the friction noise of ABS material was mainly generated by the stick-sliding phenomenon,and the friction noise of the material from the relative sliding related to the△F that was the key factor for reducing the friction noise.（3）The microspheres of the aluminum packaged by poly（D4-MMA-BA）were successfully prepared by the centrifugal spray drying after process optimization using aluminum silver paste as metallic material and the core-shell poly（D4-MMA-BA）as the packaged material.The obtained microspheres were adopted for the preparation of the free-spraying PC metallic material,which would prevent the occurrence of the flow mark and increase the low-temperature toughness of the composite.The dispersion of aluminum microspheres in PC and the effects of the microspheres content on the mechanical properties,appearance of flow mark,thermal stability and melt flow were also studied,and were characterized by the TG,differential scanning calorimetry（DSC）,SEM and the element analysis（EDS）.It showed that curing reaction of poly（D4-MMA-BA）occurred and the aluminum was successfully packaged by poly（D4-MMA-BA）polymer,forming the microspheres or flake morphology.The aluminum microsphere could greatly improve the impact strength of the PC,especially the low temperature impact strength.Compared with the PC/Al composite,the impact strength and the low temperature impact strength of the PC/aluminum microsphere increased by 47.2%and48.8%,respectively.The packaged of aluminum powder with poly（D4-MMA-BA）could obviously destroy the lamellar structure of the orientation of aluminum powder,thereby improving the weld line and flow mark on the composite.（4）A light stabilizer compound of 2-（2’-propionyloxy-5’-methylphenyl）benzotriazole（AMB）was synthesized by the esterification of the 2-（2’-hydroxy-5’-methylphenyl）benzotriazole（UV-P）with acryloyl chloride（AC）,and the AMB was then copolymerized with the acrylate and silicone monomers to prepare the silicone modifier of the core-shell poly（D4-MMA-BA-AMB）with light stability.The poly（D4-MMA-BA-AMB）was used as the light stabilizer and added into the PC to prepare the PC composite with high toughness and weather resistance.Effects of the AMB monomer on the conversion and polymerization stability,and the toughening and photostabilizing effects of the poly（D4-MMA-BA-AMB）on the PC were studied.Meanwhile,the aging mechanism of the AMB was explored.The prepared multifunctional modifier and the PC composite were characterized by FTIR,nuclear magnetic resonance spectroscopy（¹H-NMR）,TG,TEM,DLS and ultraviolet absorption spectroscopy.The target product of AMB was synthesized and the poly（D4-MMA-BA-AMB）modifier with core-shell structure were successfully prepared using the emulsion polymerization.It showed that the AMB possessed good ultraviolet absorption property by the chain scission of producing benzotriazole（UV-P）.The incorporation of the AMB had negative effects on the polymerization stability while improved the thermal stability of the modifier.The obtained poly（D4-MMA-BA-AMB）modifier could effectively absorb the ultraviolet rays.Although the addition of the poly（D4-MMA-BA-AMB）modifier had a negative effect on the tensile strength of the PC,it could greatly improve the low temperature notched impact strength,toughness performance and yellowness performance of PC products after UV irradiation.Compared with the silicone modifier,the modifier of the poly（D4-MMA-BA-AMB）had better anti-ultraviolet irradiation property.The PC/poly（D4-MMA-BA-AMB）composite had higher retention of tensile strength and impact strength and less color change after 1000 h of ultraviolet irradiation in comparison with that of the PC/poly（D4-MMA-BA）composite.Moreover,the PC/poly（D4-MMA-BA-AMB）had better aging resistance after water boiling than the composite of PC/poly（D4-MMA-BA）/UV-P.（5）The core-shell modifier of the poly（D4-MMA-BA-AMB）was added into the PVC wood-plastics material to improve the weather resistance,flame retardancy and toughness,and the effects of the poly（D4-MMA-BA-AMB）on the flame retardant,mechanical properties and anti-aging performance of the composite were investigated.The products were characterized and tested by the cone calorimeter instrument,optical microscope,chromatic aberration tester and aging test box.Results showed that the poly（D4-MMA-BA-AMB）could improve the notched impact strength of PVC-WPC,and possessed higher toughening effect than that of other organic silicon modifiers.The PVC-WPC with excellent flame retardant performance and weather resistance could be obtained by adjusting mass ratio of the white wood powder,modifier and molybdenum trioxide（Mo O₃）.The optimal ratio of the PVC-WPC was:5%white wood powder,2.5%silicone modifier and 1.5%Mo O₃.The complex of the poly（D4-MMA-BA-AMB）and Mo O₃into the PVC-WPC could reduce the smoke release and heat release rate,and increase the rate of carbon residue and the dense of the forming carbon layer,resulting in the excellent flame-retardant properties of material.Meanwhile,the incorporation of the poly（D4-MMA-BA-AMB）could also improve the weather resistance of the PVC-WPC.When the poly（D4-MMA-BA-AMB）content was 3.5%,the PVC-WPC showed excellent weather resistance and the appearance of the composite had no obvious color change after 1000 hours of accelerated aging.Moreover,the poly（D4-MMA-BA-AMB）increased the melt viscosity of the PVC-WPC during the extrusion process.When the poly（D4-MMA-BA-AMB）content was2.5%,the PVC-WPC possessed good mechanical properties and appropriate pore size through the optimization of the foaming process.更多还原