摘要:

AbstractFour new fluoropolymers were pyrolyzed in a vacuum to study rates of volatilization and to identify decomposition products. The polymers thus studied were polyperfluoropropylene, polyperfluoroheptene, poly‐4‐chloroperfluoroheptadiene‐1,6 and poly (1,2,2‐triflluorovinyl phenyl ether). Polyperfluoropropylene yielded 100% monomer at temperatures of 300 to 400°C gave an activation energy of 56.6 Kcal/mole. Polyperfluoroheptenes of different molecular weights also yielded 100% monomer on heating. However, they had lower thermal stability than polyperfluoropropylene, but a higher activation energy and a higher pre‐exponential factor. Poly‐4‐chloroperfluoroheptadiene volatilized at a rate of approximately 1% per minute at 380°C. There was very little monomer produced on thermal decomposition and an activation energy of 60 Kcal/mole was obtained from rates of volatilization at 362, 374, and 381°C. Poly (trifluorovinyl phenyl ether) showed a 25% carbonized residue at 500°C pyrolysis. The polymer decomposes into fragments containing very little monomer. Undesirable low molecular weight components in the polymer are still

ISSN:0032-3888    

DOI:10.1002/pen.760040112

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractPyrolysis in vacuum of gamma‐irradiated polytrifluoroethylene indicates increased rates of volatilization with increased dosage. At the higher radiation doses, the rate curves no longer show a maximum but resemble those previously obtained with branched polyethylenes. Studies of swelling with acetone indicate crosslinking increases with radiation dose. It is estimated that for each chain fracture caused by radiation there are approximately seven crosslinks formed. However, in addition to the crosslinks a branched structure is also being produced as evidenced by the character of the thermal degradation rate curves. Alkali treatment of the polymer sensitizes it towards dehydrofluorination and double bond formation. Subsequent rate and pyrolysis studies showed the formation of very stable residues, indicating a relatively greater thermal stability of the main chai

ISSN:0032-3888    

DOI:10.1002/pen.760040113

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

摘要:

AbstractMuch past confusion has originated from attempts to describe the complete optical properties of a plastic in terms of a few ill‐defined parameters. Simple light‐scattering theory and studies of morphology have been combined in this article to suggest the causes of polymer opacity; methods cited for the improvement of transparency and properties of reflectance have been re‐examined in this light. It is concluded that the optical properties displayed by a polymer which is allowed to crystallize without external stress depend on fundamental molecular and morphological parameters. The extent to which these inherent characteristics can be modified depends on such widely different factors as the Tg of the polymer and the physical form of the desired ar

ISSN:0032-3888    

DOI:10.1002/pen.760040114

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760040115

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY

ISSN:0032-3888    

DOI:10.1002/pen.760040101

出版商:Society of Plastics Engineers, Inc.    

年代:1964

数据来源: WILEY