摘要:

AbstractRadical copolymerization of citraconic anhydride (CAn) with isobutyl vinyl ether (IBVE) was studied as well as the copolymerizations ofN‐alkylcitraconimides, dialkyl citraconates and mesaconates with IBVE. All the copolymerizations attempted except one, incorporatingN‐alkylcitraconimide, were found to give alternating copolymers with molecular weights of more than 10,000 in most cases. Of all the copolymerizations, the CAn‐IBVE system showed the highest reactivity. A charge transfer complex between these two monomers was confirmed to exist in this system. The equilibrium constant of the complex formation was determined by UV spectroscopy as 0–162 litre/mol in CHCl3at 15°C.The alternating copolymer obtained from CAn with IBVE was converted to the corresponding copolymer of dialkyl citraconate by esteri

ISSN:0959-8103    

DOI:10.1002/pi.4990260202

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe addition of both a solid and a liquid rubber to an epoxy resin has been shown to strongly increase the toughness of the material. Moreover, it is well known that toughening depends on the morphology of the system, which, in turn, depends on the cure conditions.In the present work the morphologies of epoxy resins modified with mixtures of solid and liquid rubbers have been studied through transmission electron microscopy. An investigation of the influence of the elastomers and of the gel time on the morphology of the hardened material was carried out. Gel times were evaluated, through rheological measurements, at different cure temperatures.

ISSN:0959-8103    

DOI:10.1002/pi.4990260203

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractPoly(oxy‐2,6‐dimethyl‐1,4‐phenylene) (PPE) reacts with 1,2,4‐triazoline‐3,5‐diones to give poly([oxy‐2,6‐dimethyl‐3‐(1′, 2′,4′‐triazolidine‐3′,5′‐dione)‐1,4‐phenylene]‐co‐poly[oxy‐2,6‐dimethyl‐1,4‐phenylene]). Miscibility of these highly polar PPE copolymer with PS is probed for varying degree of polar substitution and various functional groups in the 4‐position of the heterocycle. The copolymers are miscible with polystyrene up to concentrations of counits of about 10%. For a selected blend system of PS and PPE modified with 4% of 4‐(4‐hydroxy‐3‐nitrophenyl)‐1,2,4‐triazoline‐3,5‐dione the concentration of PS was varied. Glass tion with

ISSN:0959-8103    

DOI:10.1002/pi.4990260204

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe kinetics of difunctional ionic polymerization with monomer transfer and without assumption of instantaneous initiation is studied theoretically. The set of kinetic differential equations is rigorously solved by way of graphical theory. Expressions for the molecular weight distribution (MWD) function, the number‐ and weight‐average degrees of polymerization, and the distribution of functionality are obtained. A procedure is proposed for calculating the MWD curve and the values of other molecular paramet

ISSN:0959-8103    

DOI:10.1002/pi.4990260205

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe viscosities of dimethyl formamide solutions of acrylonitrile‐acrylate copolymers were determined at 30,35,40 and 45°C using an Ubbelohde viscometer. The viscosities of homopolymer solutions were also studied. The homopolymers of aerylonitrile and also of methyl, ethyl and butyl acrylates were synthesised in the laboratory. The random copolymers were synthesised by a solution polymerisation technique keeping the acrylonitrile: acrylate ratio as 1:1, 1:2 and 1:3 (w/w). The intrinsic viscosity for each system was computed as a function of temperature. The activation parameters of viscous flow were calculated using the Frenkel‐Eyring equation. Voluminosity for all systems was also computed. From intrinsic viscosity and voluminosity data it was concluded that the polymer molecules are spherical in the dimethyl formamide solut

ISSN:0959-8103    

DOI:10.1002/pi.4990260206

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractVarious poly(arylsilane)sThe poly(carbosilane)s prepared in this way are of higher molecular weight than when prepared by the Wurtz‐type condensation route previously reported. TG shows 40–50% overll weight loss attained at 500–

ISSN:0959-8103    

DOI:10.1002/pi.4990260207

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractValues of intrinsic viscosity [ζ] measured in 2,2,2‐trifluoroethanol (TFE) and in 1·0M aq. NaCl solution mean square radii of gyrations2zand weight‐average molecular massesMwmeasured in TFE at 298 K for 12 well fractionated poly[N‐(3‐sulphopropyl)‐N‐methacrylooxyethyl‐N,N‐dimethylammonium betaine] (PSPE) samples have been used to derive the unperturbed dimensions (

ISSN:0959-8103    

DOI:10.1002/pi.4990260208

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractGrafting of butyl acrylate‐maleic anhydride copolymer on to LDPE was carried out by a solution polymerization technique. All the PA‐6/LDPE/LDPE‐g‐(BuA‐co‐MA) blends were prepared by a two‐step melt mixing technique. The blends were characterized by their morphology, mechanical properties and water absorption. By addition of just 2·4% of the LDPE‐g‐(BuA‐co‐MA), degree of grafting 12%, a remarkable improvement in the impact strength along with a reduction in water absorptio

ISSN:0959-8103    

DOI:10.1002/pi.4990260209

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe anionic polymerization of monomers such as acrylonitrile (AN) and ε‐caprolactone by triethylenediamine (TEM)/epoxide complex was investigated. They were not polymerized by TEM alone but polymerized easily with the addition of various epoxides. When glycidyl methacrylate (GMA) and allyl glycidyl ether (AGE) were used as the epoxide component, a double bond was introduced at the end of the polymer. Thus the macromonomers were prepared with the polymerization by TEM/GMA and TEM/AGE complexes. Macromonomers prepared with GMA were copolymerized with comonomers such as AN, styrene, acrylamide and methyl methacrylate to prepare the graft copolyme

ISSN:0959-8103    

DOI:10.1002/pi.4990260210

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractInjection moulded tensile bars of several amorphous and semi‐crystalline thermoplastic polymers have been deformed uniaxially to a macroscopic strain of 40% so that they showed necked and unnecked regions. From both the necked and unnecked regions of the tensile bars the specific heat and the thermal expansion coefficient were measured. The specific heat of the necked regions decreases about 20% with respect to unstrained samples for semi‐crystalline polymers at temperatures between 40°C and 60°C and for amorphous polymers at temperatures between 50°C and 70°C. The thermal expansion coefficient becomes negative at these temperatures. A smaller negative expansion coefficient is observed even in the unnecked region although nearly no change in specific heat can be observed. There is also an increase in the heat of fusion of the semi‐crystalline specimens of the necked region. Strain rate dependent effects on specific heat and thermal expansion were not observed within the accuracy of thermal

ISSN:0959-8103    

DOI:10.1002/pi.4990260211

出版商:John Wiley&Sons, Ltd    

年代:1991

数据来源: WILEY