Study On The Synthesis And Performance Of Functional Polystyrene Composite Beads

With the increasing competition of polystyrene (PS) material at home andabroad market, the new requirements for the polystyrene and expandable polystyrene(EPS) are put forward in construction; daily life field and so on. Various newproductions of PS and EPS are developing in the direction of high performance;environment-friendly and multifunction. Consequently, it's significant for studyingand developing new products of functional polystyrene from the viewpoint oftheoretical research and practical application.In this paper, on the basis of industrial large scale production process of EPSbeads, various composite beads are synthesized via the modification of inorganicpowders and in situ suspension polymerization, such as PS/CB; colorized PS;magnetic PS; antistatic EPS beads and so on. Moreover, the properties of achievedfunctional polystyrene beads are systematically investigated. These researchesprovide the experimental fundaments and theoretical evidences for the industriallarge scale production of functional EPS beads.In the second chapter, two kinds of carbon black are modified by SDBS, then aseries of polystyrene/carbon black (PS/CB) beads have been successfully synthesizedvia one-step technique of in situ suspension polymerization, the achieved beadspossess an uniform size, black luster and good morphology. Effects of modified CBcontent and initiator dosage on the polymerization time are systematically examined,moreover, the role of supplemental SDBS and dispersant in the in situ suspensionpolymerization is discussed,and a possible mechanism of in situ suspension ofstyrene in the presence of modified CB is interpreted. Our proposed technique notonly avoids the drawback of poor miscibility between the CB and PS, but alsosimplifies the synthesis technique.In the third chapter, based on inhibition phenomenon of CB in previous chapter,we are mainly focused on how to weaken or eliminate the inhibition phenomenon ofMLCB during suspension polymerization of styrene. It's interesting to note that thepolymerization time is largely shortened in the presence of a certain PVA. And theeffect of PVA dosage on the polymerization time; black luster and themacromorphology of obtained PS/MLCB beads are systematically investigated, aswell as the correlation between the PVA dosage; polymerization time and MLCB content. Based on comprehensive consideration of polymerization time,macromorphology and black luster of PS/MLCB beads, the optimum PVA dosagefor a given MLCB content is determined. In addition, the potential mechanism aboutthe role of PVA in eliminating the inhibition phenomenon of MLCB during thesuspension polymerization of styrene is also proposed and analyzed in detail.In the fourth chapter, hydrophilic Fe3O4is modified by an organic modifier viachemical reaction to obtain the hydrophobic Fe3O4. Colorized and magneticpolystyrene/Fe3O4(PS/Fe3O4) beads are successfully synthesized via in sitususpension polymerization of styrene for the first time. A series of PS/Fe3O4beadswith different color are obtained by varying the modified Fe3O4content. The effectsof modified Fe3O4content; stirring speed and surfactant dosage on the particle size ofPS/Fe3O4beads are examined, and the results demonstrate that the color and particlesize of PS/Fe3O4beads can realize the controllable synthesis. HRSEM and elementFe and O mapping results of PS/Fe3O4bead transect indicate that the Fe3O4is welldispersed in the polystyrene matrix. Three kinds of different inorganic pigments aremodified according to the modification process of the Fe3O4, and different colorizedPS beads are successfully achieved via the in situ suspension polymerization, whichdemonstrates that the modification process and the synthesis process possess thegood versatility and applicability. Consequently, a facile and versatile method isdeveloped for industrial large scale production of colorized polystyrene andexpandable polystyrene beads, and this self-developed synthesis method fills thedomestic gap of one step synthesis technique of colorized polystyrene beads.In the fifth chapter, a novel method of swelling-based and in situ polymerizationof aniline is proposed, and a series of antistatic Expandable Polystyrene/Polyaniline(EPS/PANI) composite beads are successfully synthesized with this method for thefirst time. The fire disaster that resulted from the electrostatic phenomenon duringthe industrial pre-expansion process of EPS or transportation can be effectivelyavoided. The novelty of this method lies in anchoring the nanostructured PANI onthe surface of swollen EPS beads during the in situ polymerization of aniline. Theresultant EPS/PANI composite beads not only possesses a low surface resistance thatcan fully meet the demand for avoiding the electrostatic phenomenon, but also keepsa perfect spherical profile of EPS beads without destroying the expansion system. The EPS/PANI composite beads possess a unique core/shell structure and a lowPANI content, which not only decreases the cost, but also improves the thermalstability. The effects of swelling process, the ratio of swelling agent and swellingtime on EPS/PANI beads are systematically investigated, moreover, the interrelationsbetween swelling time, surface resistance and PANI content of EPS/PANI beads arediscussed. Based on the SEM images and optical photographys of EPS/PANI beads,the synthesis mechanism is interpreted.