摘要:

AbstractRing‐opening polymerization of 2‐methyl‐2‐oxazoline produces poly(N‐acetylethylenimine). This polymerization reaction proceeds in living mechanism under appropriate reaction conditions. The resulting polymer has high hydrophilicity and good compatibility with other organic polymers. On the basis of these characteristic properties, i.e., high hydrophilicity and the cleanness of polymerization reaction, the following three functional polymers have been explored.1. Non‐ionic hydrogels,2. Non‐ionic surfactants,3. Molecular hybrid wi

ISSN:0258-0322    

DOI:10.1002/masy.19910510103

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThe synthesis and p‐ and n‐doping of polyacetylene, (CH)x, the prototype conducting polymer or “synthetic metal” is described together with a qualitative description of its band structure and changes in band structure on doping to yield positive and negative solitons. Other conducting polymers are briefly discussed. The polyanilines, a large class of versatile conducting polymers involving a novel non‐redox doping process, considered as being of significant commercial technological importance are discussed in particular with reference to their ease of processing. Present and future technological uses of conducting polymers

ISSN:0258-0322    

DOI:10.1002/masy.19910510104

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractMiscibility of polycarbonate (PC)/poly (arylate) (PAr) was studied by differential scanning calorimetry (DSC), phase contrast microscopy with digital image analysis (DIA) system, FT‐IR spectroscopy, and cloud points for the PC/PAr/methylene chloride ternary systems. PC and PAr were immiscible over the whole composition range from the thermodynamical viewpoint. However, PC/PAr is homogenized by transesterification between PC and PAr at high temperatures. There is observed a competition between phase separation due to thermodynamical factor and phase dissolution due to transesterification. The pattern of the phase separation was spinodal decomposition type and the structure was successfully analysed by DI

ISSN:0258-0322    

DOI:10.1002/masy.19910510105

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractPrevious work has demonstrated that compatible blends of main‐chain liquid crystal polymers (LCP) with side‐chain LCP's can be prepared. The present work was carried out to extend the scope and application of this finding to liquid crystal polyesters, similar to commercially available LCP's and to demonstrate the effect of the blend composition upon the physical and mechanical properties. A series of melt‐processable main‐chain polyesters was prepared as well as a series of acrylic polymers and copolymers which possess a side‐chain mesogenic unit, similar to that of the main‐chain LCP's. While the results of the blending studies of these high molecular weight materials were somewhat ambiguous as to compatibility, there are strong indications that the presence of the side‐chain mesogen containing polymers does result in an improvement in the overall mechanical properties of the m

ISSN:0258-0322    

DOI:10.1002/masy.19910510106

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractWe report the results of theoretical and experimental studies of styrene‐co‐vinyl phenol (STVPh) copolymer blends with poly(n‐octyl methacrylate) (POMA) and poly(n‐decyl methacrylate) (PDMA). This work is a natural extension to our recently reported studies of the phase behavior of analogous STVPh blends with poly(n‐butyl methacrylate) (PBMA) and poly(n‐hexyl methacrylate) (PHMA) where we employed an association model together with parameters obtained from studies of miscible homopolymer blends. The theoretically calculated miscibility maps for STVPh copolymer blends with the homologous series of poly(n‐alkyl methacrylates) (PAMA) are in fine agreement wi

ISSN:0258-0322    

DOI:10.1002/masy.19910510107

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractHydrophilic/hydrophobic, cationic/anionic polyurethane membranes were prepared and the effect of the synthesis pressure and temperature on the morphology were evaluated. The pervaporation characteristics of the membranes for the separation of ethanol/water mixture as well as the gas separation performances in the separation of nitrogen/oxygen mixture were measured and the effect of the IPN synthesis parameters were analyzed.

ISSN:0258-0322    

DOI:10.1002/masy.19910510108

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractPoly(phenylene ether ketones) were prepared by polyacylation reactions in hydrogen fluoride‐boron trifluoride and by aluminum trichloride promoted Friedel‐Crafts reactions modified by Lewis bases. Structural and engineering properties of these polymers are presen

ISSN:0258-0322    

DOI:10.1002/masy.19910510109

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractNew synthetic methodology was developed as part of an effort to increase the processibility of high Tg polyimide homo−and copolymers, suitable as matrix resins and structural adhesives. Molecular weight and end group control together with solution imidization techniques were successfully employed to convert a variety of poly(amic acid) intermediates to fully cyclized polyimides. The solution imidization was conducted in N‐methylpyrrolidone (NMP) with o‐dichlorobenzene used as the azeotroping agent at 165–190°C. This technique has produced products which are more soluble than polyimides prepared previously by bulk thermal cyclization of poly(amic acids) at temperature of 300°C. They are also more stable than “chemically” imidized materials. In addition, incorporation of the monofunctional reagent phthalic anhydride provides nonreactive phthalimide end groups and controlled molecular weight. This latter feature significantly further improved the melt and solution processibility of the resulting polyimides. In this study thermoplastic, fully cyclized polyimides of 10 000, 20 000, and 30 000 M̄n were prepared which displayed glass transition temperatures ranging from 260–353°C, with the highest Tgobserved with phthalimide capped polyimide systems derived from 6F‐dianhydride and p‐phenylene diamine. Tough, transparent films were prepared from polymers of 20 000 and 30 000 g/mol by casting from NMP solution or by compression molding at 50–70°C above the glass transition temperature. For purposes of molecular weight assessment, t‐butyl phthalic anhydride was used as the end blocker. This permitted 400 M‐Hertz proton NMR to be used for assessing the concentration of end groups. Comparison of the 18 aliphatic protons at the end of the chain allowed M̄n values to be determined, which agreed well with theory.A series of poly(arylene ether ketone)/aromatic polyimide blends were investigated to determine the influence of structural variation and composition on miscibility. As an extension to the PEEKTM/UltemTMblend system, which has been reported to be miscible over all proportions, this study examined how structural variations in both the poly(arylene ether ether ketone) and the polyimide portions affect miscibility. In particular, replacement of the hydroquinone fraction in PEEKTMwith bisphenol A or sulfonyl diphenol produced an amorphous polymer which was no longer miscible with UltemTM. Polyimide structures modified by employing 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride (BTDA) and 4,4′‐[1,4‐phenylene‐bis‐(1‐methyl ethylidene)] bisaniline (Bis P) diamine to obtain higher glass transition temperatures were also investigated. This system afforded homogeneous blends with PEEKTMwhen the (Bis P) diamine was utilized in the synthesis of the polyimide. Furthermore, up to 50 mole percent of hexafluoro‐bis‐dianhydride (6FDA) could be substituted for BTDA without loss of miscibility. However, when the more polar 3,3′‐diaminodiphenylsulfone diamine was employed, immiscible blends resulted. An additional important variant has been to incorporate polyimide siloxane segmented copolymers into the PEEKTMblend system. The polyimide segment can be designed to be miscible whereas the siloxane portion is homogeneously dispersed into a second phase which, in fact, enriches the surface behavior quite dramatically in siloxane content. The latter could be of some importance in allowing for atomic oxygen res

ISSN:0258-0322    

DOI:10.1002/masy.19910510110

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractA new method for modelling polymerization kinetics is described in which numerical integration is used to provide the time scale for the polymerization experiment and Monte Carlo methods are employed to calculate the instantaneous molecular weight distribution, detailed chain composition, and chemical heterogeneity of the polymer as a function of time/conversion. The method has been applied in simulations of styrene‐methyl methacrylate copolymerization and styrene‐hydroxyethyl acrylate‐butyl acrylate terpolymeriz

ISSN:0258-0322    

DOI:10.1002/masy.19910510111

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractWholly aromatic, thermotropic liquid crystalline (LC) terpolyesters made from 6‐hydroxy‐2‐naphthoic acid (HNA) and 4,4′‐biphenol (BP) as key components have been prepared and evaluated for utility as high performance fiber precursors. The processability and fiber properties of a specific composition (1) made from both HNA and BP were compared with those of a more well‐known LC terpolyester made from p‐hydroxybenzoic acid, tere‐ and isophthalic acids and BP (Ekonol®type). The advantages of polymer 1 and its high‐modulus f

ISSN:0258-0322    

DOI:10.1002/masy.19910510112

出版商:Hüthig&Wepf Verlag    

年代:1991

数据来源: WILEY