Copolymerizations of p-dichlorobenzene (DCB)/4-bromophenyl ether (BPE), DCB/4,4'-dibromobiphenyl (DBB), and DBB/BPE pairs with sodium sulfide under high temperature (270-290°C) utilizing N-methyl-2-pyrrolidinone (NMP) as solvent were carried out to give C(DCB/BPE), C(DCB/DBB), and C(DBB/BPE) copolymers, respectively. The reactivity of dihaloaromatic monomers toward thiolate anion in the polycondensation reaction followed the order DBB > DCB > BPE. The reactivity gap between DBB and DCB toward thiolate anion seemed to be smaller than that between BPE and DCB, resulting in both high yield and high molecular weight in the C(DCB/DBB) copolymers compared to C(DCB/BPE) copolymers. The copolymerization of DBB/BPE pair with sodium sulfide, which has larger reactivity gap than the DCB/ DBB or DCB/BPE pair, gave mixtures of PBS and PPSE homopolymers especially in the range of 50-80 mol % BPE in the feed. The C(DCB/DBB) and C(DCB/BPE) copolymers, however, exhibited random copolymer character in all comonomer ratios in the feed as evidenced by copolymer composition and DSC data.

Synthesis and characterization of copoly(arylene sulfide)s

PROBLEM: To provide a method of producing a polyarylene sulfide (PAS) such as polyphenylene sulfide (PPS) in which a dihalo aromatic compound and a sulfur source containing an alkali metal are polymerized in an organic amide solvent, whereby a PAS is produced at higher yield and the amount of NaCl produced as a by-product is reduced to not greater than half that of conventional methods, and, due to a dehydration step being omissible, PAS with excellent practical utility is produced with high productivity in a short time. SOLUTION: A method of producing a PAS in which a dihalo aromatic sulfide compound represented by the formula: X—(—Ar—S—) n —Ar—X (in the formula, Ar represents an optionally substituted aromatic group, X represents a halogen atom, and n is from 1 to 10) and a sulfur source containing an alkali metal are polymerized in an organic amide solvent; and a PAS of which an average particle size is from 10 to 5000 μm, a melt viscosity measured at a temperature of 310° C. and a shear rate of 1216 sec −1 is from 0.1 to 3000 Pa·s, and a nitrogen content is not greater than 500 ppm.

Method of producing polyarylene sulfide and polyarylene sulfide

Abstract The substitutions of the chlorine atoms in p-dichlorobenzene (DCB) or the chlorine end-groups of polyphenylene sulfide (PPS) by sodium N-methyl-4-aminobutyrate (SMAB) are important reactions in the polymerization of PPS. The reaction process of DCB with SMAB was studied under conditions similar to the polymerization of PPS. The molecular structures of the products were analyzed through high-performance liquid chromatography, liquid chromatography-mass spectroscopy, gas chromatography-mass spectrometry, and other methods. Several pairs of para- and meta-isomer products were found, which indicates the coexistence of both nucleophilic addition–elimination (SN2Ar) mechanism and aryne intermediate mechanism. Based on mechanism analysis, the networks of reactions of DCB with SMAB were proposed and the effects of the ratio of SMAB to DCB, water content, and temperature on the reaction process were studied.

A new insight into the reaction mechanism in preparation of poly(phenylene sulfide)

The polycondensation kinetics of 4,4’-dihydroxydiphenyl sulfide (DHPS) with 4,4’-dichloro diphenylsulfide (DCPS) was investigated in the presence of catalyst 2A. The reaction follows second-order kinetics and the reaction rate is a bimodal, a relatively lower rate initially and a faster rate after 3h. The initially lower rate is attributed to the lower solubility of DHPS salt in organic solvent. The results show higher polymerization temperature leads to higher conversion and finial reaction extent after 7h. In the present work, catalyst 2A/DHPS molar ratio of 0.17 is considered more suitable for PPSE preparation. The activation energy of two-stage polymerization of PPSE is 104.5kJ/mol and 79.33kJ/mol, respectively. According to obtained kinetics parameters, curves of fractional conversion versus reaction time were simulated and compared with experimental curves at different temperatures.

Kinetic Study on the Preparation of Poly(Phenylene Sulfide Ether)

A kinetic study on poly (p-phenylene sulfide) formation from p-dichlorobenzene (1) and sodium sulfide reveals that the initiation rection is first order with respect to 1 and sodium sulfide, respectively. Reaction on the surface of solid sodium sulfide has proved to be negligible when the reaction is carried out in the presence of the solid. The time course of the concentration of 1 and its dimer can be explained with a simplified eight step kinetic model for the initial stage, in which each of the step is firest order with respect to the reactant in concern. Kinetic parameters for each of the steps were estimatied. Increase in [Na2S]/[1] ratio causes the increase both in polymer yield and in the degree of polymerization. Presence of a small amount of water enhances cosiderably the rate of polymerization and increases the polymer yield, but the highest degree of polymerization was observed in the presence of water approximately equimolar to 1.

Seiichi Ona

Papers

PPS Preparation. A Kinetic Study and the Effect of Water on the Polymerization