摘要:

AbstractInvestigations were made on the radical polymerization of styrene in presence of ethylene propylene diene terpolymers and ethylbenzene. The results obtained allowed to calculate the transfer constants of polystyryl radical to terpolymer and ethylbenzene in a mixed system. Meanwhile the same results showed a lower radical reactivity of the elastomer in presence of the aromatic transfer agent.

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270101

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe melting and crystallization behaviour of undrawn poly(ethylene terephthalate)‐nylon 6 biconstituent fibers (BCF) have been investigated by DSC measurements. A decrease of the internal ΔT between the temperature of the glass transition and the temperature of the cold crystallization has been found. Changes of the temperature of the melt crystallization of the two components depending on the blend ratios (e.g. the phase morphology) have been also observed. These effects have been explained by an interface physical interaction which changes the degree of order of the molecules inside the phases. A relation between the decrease in ΔT of the PETP component and the maximum draw ratio λmaxof the BCF has been established. It is supposed that the change in ΔT causes the occurrence of local tensions and the initial formation of microcracks in the PETP phase which lead to a decrease of

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270102

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractUn réacteur permettant de conduire des synthèses anioniques sous atmosphère inerte est décrit ici. La polymérisation anionique est facilitée et les copolymères séquencés obtenus par cette méthode présentent des distributions de masse moléculair

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270103

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractChanges in electrical properties of poly(p‐phenylene) (PPP) upon doping antimony pentachloride have been investigated. A strong influence of antimony pentachloride on electrical properties of poly(p‐phenylene) has been ascertained.Depending pressure formation, doping time, dopant concentration, the way of preparing PPP, differences in specific conductivity of doped and undoped PPP can be as much as 8 to 10 orders in magnitude.We have pointed out that thermal treatment leads to a more perfect physical structure (an increase in crystallinity and an increase in crystallite size). A more perfect physical structure of the PPP displays a much lower change in electrical conductivity as compared with a less perfect physical struct

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270104

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractEpoxy resins from bisphenol A/epichlorohydrin, 4,4′‐thiodiphenol/epichlorohydrin and 4,4′‐sulfonyldiphenol/epichlorohydrin were prepared and cured with benzidine and diaminodiphenylmethane at 140°C. The cured resins were subsequently subjected to thermal degradation. The degradation was followed by determining the frequency factor A and the activation energy E*. From the results it is concluded that the sulfone epoxy resins are thermally more stable than the bisphenol A epoxy resins cured with the same curing agent under identical experimental co

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270105

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractUnder vibratory milling conditions benzene and pyridine lead to solid products consisting of a mixture of fractions soluble in methanol and DMF and an insoluble fraction. Chromatographic and spectroscopic analyses indicate that the soluble fraction is a mixture of compounds with linear structures obtained by opening of the aromatic ring. Interaction of these compounds with oxygen, light, or high temperatures leads to crosslinked structures.

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270106

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractSodium hydroxide swelled cotton and bagasse celluloses to a greater extent than potassium hydroxide. Higher alkali concentration during xanthation favoured the dissolution of cellulose and the formation of the main sulphur byproducts. Compared to sodium hydroxide, potassium hydroxide resulted in lower dissolution of cellulose, higher degree of xanthation (γ‐number) of dissolved xanthate and greater formation of sulphur byproducts. The xanthation of the more open and accessible bagasse cellulose resulted in higher solubility, lower γ‐number of dissolved xanthate, and higher amounts of sulphide and thiocarbonate than in case of the more compact and less accessible cotton cellulose. Reducing the carbon disulphide ratio reduced the γ‐number of dissolved xanthate and the amounts of the main sulphur byproducts as well as the dissolution of cellulose. In case of xanthating cotton cellulose at the lower carbon disulphide ratio potassium hydroxide resulted in a lower γ‐number of dissolved xanthate than sodiu

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270107

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractSoda lignins separated from soda cooks of rice straw and corn stalks were found to be completely soluble in most organic solvents, while thiolignins separated from kraft cooks consist of two fractions, a soluble (A) and an insoluble (B) fraction. The carbon content of both types of lignin decreases in the order soluble>soda>insoluble, while the content of methoxy groups decreases in the order soda>soluble>insoluble.The soluble lignins isolated from kraft cooks have higher contents of phenolic OH/C9‐functions than soda lignins. The ratio of phenolic OH:OCH3is also higher for kraft lignins than for soda lignins of both rice straw and corn stalks.The calculated value for MeO/C9from nitrobenzene oxidation on the basis of molar proportion of aldehydes is higher than that determined by chemical analysis due to the presence of condensed units.1H‐NMR spectra show the percentage of condensed units in lignins from soda cooks to be much lower than from kraft cooks of both rice straw and corn sta

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270108

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractThe polyacrylamide (PAM) produced as a homopolymer byproduct during the grafting of cellulose by acrylamide was partially hydrolysed for 2 and 4 hours. The three prepared polymers besides Accostrength® 86, which is mainly a dry strength resin and also improves retention of fillers and fines, were used as filler retention aids for bleached bagasse. Three fillers were used, namely titanium dioxide, silica and kaolin. The results obtained showed that the PAM hydrolysed for 2 hours gave the best results for both filler retention and improvement of strength properties. The values obtained for this polymer were comparable with those obtained for the commercial polymer

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270109

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY

摘要:

AbstractUncured polyphenylene sulfide (PPS) may form a perfect spherulite structure with a diameter of the spherulites larger than 100 μm. On the free surfaces of uncured PPS samples after isothermal crystallization a variety of spherulite patterns can be observed by means of scanning electron microscopy (SEM). However, the crystalline morphologies of PPS are greatly affected by the curing conditions. Graphite fibres, carbon fibres, and glass fibres possess the ability for inducing the transcrystallization of PPS to a different degree. The corrosive resistance of the PPS resin is not only related to its chemical structure, but also to its aggregation structure, and furthermore to the interfacial effect of carbon fibres in the composites

ISSN:0003-3146    

DOI:10.1002/apmc.1984.051270110

出版商:Hüthig&Wepf Verlag    

年代:1984

数据来源: WILEY