Synthesis And Characterization Of Expandable Polystyrene

Expandable polystyrene is commonly used for packing and insulation materials because of versatility, dimensional stability, cleanliness and low cost. Average particle size, particle size distribution, molecular weight, molecular weight distribution and density are all the key indexes in industry. The study originates from the EPS project of Dalian Sub. of CNPC, who wants to improve the proportion of PS particle size 0.6-1.4mm and grasp the rules of the polymerization and the product data, such as molecular weight and molecular weight distribution, Tg. This paper is about the polystyrene which is synthesized via suspension polymerization at different O/W ratio, different dispersant content, different stirring rate, different heating process and electrolyte. The qualified rate was examined by grading sieve, and the best working condition was gotten. Through different analysis, the average particle size, particle size distribution, molecular weight, molecular weight distribution and Tg of the every sample are all summarized and get the rules.All organic blowing agents, such as pentanes, industrially applied as physical blowing agents for the preparation of EPS, are harmful to human health and the environment. In addition EPS is non-degradable, so we studied different blowing agents to replace pentanes, and the structure of the copolymer and matrix on the basis of the project of Dalian Sub. of CNPC. The typical process used to synthesize expandable polystyrene (EPS) was modified and applied to prepare water expandable polystyrene (PS)-starch copolymer, and maleic anhydride (MAH) improved the compatibility between starch and styrene. Various reaction conditions (weight ratio of styrene/water (O/W ratio), starch content, clay content) were applied to obtain WEPS copolymer beads as high water content as possible. And molecular weight and molecular weight distribution, glass transition temperature (Tg), and phase behavior of copolymer were investigated. The water content, molecular weight increased as function of O/W ratio, and the molecular weight distribution and the Tg value of copolymer both decreased; While, molecular weight distribution and the Tg of the copolymer both increased as function of starch content, and the molecular weight decreased. The water content in the beads reached the maximum value at 6 wt% of starch content at same O/W ratio. With the increasing of the starch content, the domain size of starch riched increased, and its size distribution was best uniformly at 6 wt% of starch. The highest of water content is 5 wt% clay content, but the particle size is very small. Main researches:1 PS was synthesized at 1:1 O/W ratio and different stirring rate from 270-350rpm, and the average particle size and particle size distribution, molecular weight and molecular weight distribution and Tg of the product were obtained at same time;2 PS was synthesized at different O/W ratio (1:2,1:1.75,1:1.5, 1:1.25,1:1) and same stirring rate 330rpm, and the average particle size and particle size distribution, molecular weight and molecular weight distribution and Tg of the product were obtained at same time;3 PS was synthesized with different dispersant at same O/W ratio and stirring rate 330rpm, and the average particle size and particle size distribution, molecular weight and molecular weight distribution and Tg of the product were obtained at same time;4 The temperature subsection is help for the polymerization at 1:1 O/W ratio;5 Polymerization process was amplification reaction in 2L reactor, and pentanes were added in the system;6 WEPS was synthesized at different O/W ratio(1:5,1:3,1:2,1:1.5, 1:1), and the average particle size and particle size distribution, molecular weight and molecular weight distribution, Tg, water content and phase structure and phase behavior of the product were obtained at same time;7 WEPS was synthesized with different starch content at same O/W ratio(1:1.5), and the average particle size and particle size distribution, molecular weight and molecular weight distribution, Tg, water content and phase structure and phase behavior of the product were obtained at same time;8 WEPS was synthesized with different clay content at same O/W ratio(1:1.5) and 5 wt% starch'content, and the average particle size and particle size distribution, molecular weight and molecular weight distribution, Tg, water content and phase structure and phase behavior of the product were obtained at same time.