摘要:

AbstractThe infra‐red spectrum of polyvinyl acetate has been studied from 4000 to 150 cm‐1 and a detailed assignment made. To assist with the assignments the partially deuterated polymer, poly‐α, α, β‐trideuterovinyl acetate, and a branched‐chain acetate have been synthesised and their spec

ISSN:0007-1641    

DOI:10.1002/pi.4980030401

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractPolyimide samples in the form of powders, films and sintered mouldings were prepared from pyromellitic dianhydride and 4,4′‐diaminodiphenyl ether. The effect of environmental variables on the oxidative stability at 400°C of the high molecular weight films was studied, and it was shown that hydrolytic processes could greatly accelerate the degradation. The higher stability of powders was attributed to the presence of low molecular weight fractions which could inhibit these hydrolytic processes. Improvement of the stability of the films by the addition of low molecular weight materials during the casting process and the destabilisation of powders by prolonged solvent extraction gave support to this hypothesis.For comparison of thermal stabilities of polypyromellitimides of differing chemical structure weight loss results should therefore be determined on high molecular weight films under controlled humidity condit

ISSN:0007-1641    

DOI:10.1002/pi.4980030402

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe reactions of various B‐dichloro‐N‐triarylborazines with boiling N,N‐dimethylformamide (DMF), and DMF in the presence of dimethylamine have been shown to give condensation polymers of the polyborazylene oxide type. The degrees of polymerisation range in individual cases from about 2–25. The presence of one ortho substituent in the N‐aryl group causes the molecular weight to fall sharply, and polymerisation is completely inhibited in the presence of two ortho substituents. Reactions of several N‐triarylborazines with boiling DMF also gave polyborazylene oxide‐type polymers together with trimethylamine. The infra‐red spectra, and thermal and hydrolytic stability of the polymers have

ISSN:0007-1641    

DOI:10.1002/pi.4980030403

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe molecular probe technique uses a standard gas chromatograph modified to obtain a printed digital record of retention time vs. column temperature to be obtained automatically. From this the observed specific retention time, Vg, can be calculated. If Vgis the theoretical value it can be deduced that: % Crystallinity = [1 − Vg/Vg′] × 100. Experimental results using Tenite 800 and Tenite 3310 polyethylene produced and sold by Eastman Chemical Products Inc., Kingsport, Tennessee, U.S.A. justify this equa

ISSN:0007-1641    

DOI:10.1002/pi.4980030404

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractThe structures of the polymers obtained in various types of heterogeneous polymerisations have been studied together with the polymerisation kinetics. Examples of these are: fibres of polymethylene and polyethylene; nylon spherulites produced in the polymerisation of lactams; and extended chain crystals of polyoxyethylene. Solid‐state polymerisation is briefly discusse

ISSN:0007-1641    

DOI:10.1002/pi.4980030405

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractApproximately seventy‐five organic materials have been detected by gas chromatography in the thermal decomposition products of PVC and are shown by mass spectrometry and retention studies to consist mainly of aromatic and aliphatic hydrocarbons. Weight‐loss experiments and time‐resolved chromatography indicate that these products are formed mainly during dehydrochlorination. The products are modified by the presence of oxygen but no oxygenated organic species have been detected.Experiments to specifically monitor the production of phosgene from the decomposition of both a rigid PVC sheet and a PVC polymer in air are recorded. Phosgene has not been detected and direct seeding techniques have been used to investigate the detection limits of this material.PVC is known to release the toxic gases, carbon monoxide and hydrogen chloride, when involved in fires. It is shown that the minor products, including phosgene, make little or no contribution to the overall toxicity of the decomposition pro

ISSN:0007-1641    

DOI:10.1002/pi.4980030406

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980030407

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980030408

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980030411

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY

ISSN:0007-1641    

DOI:10.1002/pi.4980030413

出版商:John Wiley&Sons, Ltd    

年代:1971

数据来源: WILEY