Syntheses、Characterization and Properties of Novel Phosphorus Containing Polymers

• Main Authors: Jeng-Yueh Shieh, 謝正悅
• Other Authors: Chun-Shan Wang
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/39938537987904788558

博士 === 國立成功大學 === 化學工程學系 === 88 === 英 文 摘 要 Polymers have the excellent characteristics of solvent and chemical resistance, thermal resistant, electrical and mechanical resistance properties. The versatility in formulation also made polymers widely applied industrially for fiber, engineering product, motor vehicle construction, laminates, encapsulant for semiconductor, and insulating material for electric devices . Recently, nonhalogen flame retardants have been developed to replace halogen-containing flame retardant to meet the requirements of low toxicity, low smoke and low dropping in view of health and environmental harmony. A series of various flame retardants were synthesized from 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), while DOPO was synthesized through multistep reaction from o-phenylphenol and phosphorus trichloride. The phosphorus-containing compounds were used as reactive flame-retardant in preparing polyesters, polycarbonate, epoxy resins for encapsulant of semiconductor, and insulating material for electric devices. 2-(6-oxido-6H-dibenz <c,e><1,2> oxaphosphorin-6-yl) dimethyl itaconate (ODOP-DI) was prepared by the addition reaction between 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and dimethyl itaconate. The compound (ODOP-DI) was used as a reactive flame-retardant in polyethylene 1,4-terephthalate (PET) and polyethylene 2,6-naphthalate (PEN) syntheses. A series of various flame retardant copolyesters containing various amount of phosphorus were synthesized by direct esterification process using the compound of [(6-oxido-6H-dibenz <c,e><1,2> oxaphosphorin-6-yl)methyl]-butanedioic acid (ODOP-BDA) and bis (hydroxyethyl) terephthalate (BHET) or bis (hydroxyethyl) naphthalate (BHEN). The copolyesters having inherent viscosity of 0.511~0.635 dl/g were obtained in quantitative yield. The thermal properties of the resulted flame retardant copolyesters were investigated by the differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). Owing to the incorporation of the rigid structure of DOPO and pendant P group, the resulted phosphorus containing copolyesters exhibited better flame retardancy, higher char yield and thermal stability than homopolymers of PET and PEN. UL 94-VO rating could be achieved with a phosphorus content of as low as 0.75% for PET, 0.5% for PEN and no fume and toxic gas emission were observed. Novel P-containing copolycarbonate was prepared via melt poly- condensation of diphenyl carbonate (DPC), bisphenol-A (BPA) and 2-(6-oxid-6H-dibenz<c,e><1,2>oxa-phosphorin-6-yl)1,4-benzenediol (ODOPB). The copolycarbonates were characterized by infra-red spectra, reduced viscosity, and differential scanning calorimetry. The copolycarbonates with reduced viscosities of 0.21~0.25 dL/g were obtained in quantitative yields. These phosphorus containing copolycarbonates have excellent thermal and flame retardant properties. Owing to the incorporation of the rigid structure of ODOPB and the pendant P group, the resulting phosphorus containing copolycarbonates exhibited better flame retardancy, higher char yield, higher degradation temperature and thermal stability than homopolymers of polycarbonate (PC). High LOI value and UL 94-VO rating could be achieved with a phosphorus content of as low as 0.75% for PC, and no fumes or toxic gas emissions were observed. A reactive main-chain phosphorus-containing diol compound, bis (3-hydroxyphenyl) phenyl phosphate (BHPP), was synthesized. The compound (BHPP) was used as a reactive flame-retardant for diglycidyl ether of bisphenol-A (DGEBA). The side-chain compound (ODOPB) was used as a reactive flame-retardant in o-cresol formaldehyde novolac epoxy resin (CNE) for electronic application. The resulting both type phosphorus-containing cured epoxy resin(BHPP and ODOPB) exhibited better flame retardancy than the regular bromine containing flame retardant epoxy resin in encapsulation application. But The main-chain phosphorus-containing BHPP epoxy resin showed lower weight loss temperature and lower glass-transition temperature(Tg). Owing to the rigid structure of ODOPB and pendant P group,the resulted phosphorus containing epoxy resin exhibited better flame retardancy, higher glass transition temperature and thermal stability than the regular bromine containing flame retardant epoxy resin. UL 94-VO rating could be achieved with a phosphorus content of as low as 1.1% (comparable to bromine content of 6%) in the cured resin and no fume and toxic gas emission were observed. A phosphorus-containing epoxy resin, 6-H-dibenz[c,e][1,2] oxaphosphorin 6-[2,5-bis(oxiranylmethoxy) phenyl]- 6-oxide (DOPO epoxy resin), was synthesized and cured with phenolic novolac (PN), 4,4''-diaminodiphenylsulfone (DDS), or dicyanodiamide (DICY). The reactivity of three curing agents toward DOPO epoxy resin was found in the order of DICY> DDS> PN. Thermal stability and the weight loss behavior of the cured polymers were studied by TGA. The phosphorus-containing epoxy resin showed lower weight loss temperature and higher chair yield than that of Bisphenol-A based epoxy resin. The high char yields and limited oxygen index (LOI) values as well as excellent UL-94 vertical burn test results of DOPO epoxy resin indicated the effectiveness of phosphorus-containing epoxy resins as a flame retardant. The DOPO epoxy resin was investigated as a reactive flame-retardant additive in electronic encapsulation application. The resulted phosphorus containing encapsulant also exhibited better flame retardancy, higher glass transition temperature and thermal stability than the regular encapsulant containing the brominated epoxy resin. High LOI value and UL-94 V-0 rating could be achieved with a phosphorus content of as low as 1.03% (comparable to bromine content of 7.24%) in the cured epoxy and no fume and toxic gas emission were observed.