摘要:

AbstractThe wettability of poly(ethylene terephthalate) films is an important criterion for their industrial use. The attainment of that property is realized by treatment of the material under corona discharge. The purpose of this article is to describe the influence of the principal parameters of the discharge on the modification of the surface properties; the influence was measured by physicochemical methods (ESCA, contact angle). The results prove that the most important physical parameters of the discharge are the wire‐cylinder distance, the current intensity, and the time of treatment. The analysis shows that the fixed species are oxygen and nitrogen in the form of carboxylic functions and amines or nitrogen oxides. In any case, the correlation between free surface energy and concentration of fixed chemical species shows that the surface properties depend on the chemical functions introduced into the material by the discharg

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200601

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe interaction of poly(ethylene oxide) with alkali picrates in tetrahydrofuran and dioxane was studied by optical and NMR spectroscopy and conductance measurements. Evidence was found of the formation of two kinds of solvation complex, differing in the nature of the ion pairs involved. A strong anion effect on cation binding to the polyether was demonstrated.

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200602

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe copolymerization of methylenedioxolanes, such as 4‐methylene‐1,3‐dioxolane (I) and 2,2‐dimethyl‐4‐methylene‐1,3‐dioxolane (II), with maleic anhydride (Manh) gives rise spontaneously to the alternating copolymers by the participation of charge‐transfer (CT) complexes. The formation of CT complexes I‐Manh and II‐Manh was ascertained by UV and NMR spectroscopies. The equilibrium constants(K)could not be determined but were assumed to be small (K≪ 1). For comparison with these systems an investigation of I‐dimethyl maleate (DMM) and II‐DMM systems was carried out to estimateKvalues 0.115 and 0.157 L/mol, respectively. To clarify the copolymerization mechanism I‐Manh‐acryronitrile was terpolymerized. Consequently it was concluded that the spontaneous copolymerization of I‐Manh and II‐Manh systems is effected

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200603

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe reaction of PVA with 2,2‐dialkoxyethoxystyrylpyridinium or quinolinium salts is described. The resultant water‐soluble polymers, which contain small amounts of the styrylpyridinium‐ or quinolinium group, exhibited high photosensitivity. Among the polymers prepared PVA‐bearing 4‐oxystyrylquinolinium group was photoinsolubilized with visible light that corresponded to an ar

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200604

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe reaction of poly(vinyl alcohol) with styrylpyridinium and quinolinium salts which contain formyl group produced water‐soluble photosensitive polymers. The sensitivity was high, although the content of the styryl groups was extraordinarily low. Spectroscopical studies revealed that the high sensitivity is due to the aggregation of photofunctional group in the polymer matrix which leads to cyclodimerization on exposure to ultraviolet (UV) ligh

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200605

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractA new catalyst system (Ph3SiCOPh‐aluminum complex‐alcohol) was investigated for photopolymerization of cyclohexene oxide. Polymer conversion and molecular weight increased with polymerization time. When a Ph3SiCOPh‐Al (n‐Praa)3‐alcohol catalyst system was used the catalyst activity decreased, depending on the alcohol:i‐PrOH>n‐PrOH>i‐BuOH>MeOH>t‐BuOH>H2O. When the Ph3SiCOPh‐Al complex‐i‐PrOH catalyst system was used the catalyst activity decreased, depending on the ligand of the Al complex: ß‐ketoester>orthocarbonyl phenol>ß‐diketone. Benzophenone derivatives were effective for catalyst ac

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200606

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractModel hard segments from MDI and different chain extenders have been studied by DSC. Among the studied α‐ω alkane diol‐type chain extenders, all giving crystalline hard segments, butane diol shows the highest melting temperature, while other types such as 1,4‐diaminobutane, 1,4‐benzene dimethanol, and 4,4′‐methylene‐bis(2‐chloroaniline), so‐called MOCA, have no melting endotherm in the range 30–260°C. In addition to DSC, dynamic mechanical properties were measured on linear block polyurethanes having both hard segments and soft ones of hydrogenated 1,2‐polybutadiene. The hard segments in the polyurethane chains are of amorphous structure or low crystallinity, and their high‐temperature behavior depends only on their strength of interaction in the amorphous state. Accordingly, MOCA shows the highest hard

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200607

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe pyrolysis products of a model urethane prepared from trimethylolpropane (TMP) propoxylated with 3, 3, 3‐d3‐propylene oxide and PAPI have been extensively studied by gas chromatography in conjunction with electron‐impact, chemical‐ionization, and field‐ionization mass spectrometry. The isotope distributions for some of the lower‐molecular‐weight species (determined by electron‐impact and/or field‐ionization mass spectrometry) showed a greater amount of H/D mixing than was expected from previously postulated concerted mechanisms. The deuterium distributions of the higher‐molecular‐weight TMP species were, in general, consistent with previously described mechanisms. The results from this study support the proposal that pyrolytic degradation of urethanes occurs mainly by a systematic sequence of concerted reactions. However, the deuterium distributions in some compounds indicate that free‐radical reactions are important in the format

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200608

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe synthesis of polymer‐bound thiol reagents, supported on macroporous 4% divinylbenzene co‐polymer (Amberlite XE‐305), via three synthetic approaches is described: (i) Alkylation or acylation of XE‐305 with 3‐nitro‐4‐halogen‐substituted benzyl chloride or benzoyl halide yielding 3‐nitro‐4‐halobenzene‐bound species, followed by substitution of the activated polymeric halogen atom with sulfur (see Scheme 1). (ii) Formation of a thiol ether by a direct substitution of an active polymeric halogen by reaction with benzylthiol, followed by chlorination, thiolation, and reduction (see Scheme 2). (iii) Attachment of a prepared tailor‐made disulfide to aminomethyl function of a polymeric support, followed by reduction (see Scheme 3). The polymers were tested for their free‐thiol content by 5, 5′‐dithiobis(2‐nitrobenzoic acid) (Ellman's reagent12) in DMF. Their thiolytic activity was investigated in the removal of 2‐nitrophenylsulphenyl (Nps) group from Nps‐protected amino acid (Scheme 4). Site‐site interaction between the polymer‐bound thiol with its activated halide precursor to yield polymeric sulfide during displacement reaction, and the interconversion of the polymeric thiols into polymeric disulfides at equilibrium or during reaction with Nps‐amino acids, observed, and is attributed t

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200609

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY

摘要:

AbstractThe propagation and termination rate constantskpandktfor the radical polymerization of butyl acrylate initiated by biacetyl have been measured by using the rotating‐sector method, in various solvents at 30°C. The value ofkpand initiation rateRivaried with solvents, while the value ofktdid not change with solvents except for benzonitrile. The variation ofkpwith aromatic solvents has a trend against Hammett σpof the solvent substituents similar to that for methyl methacrylate or phenyl methacrylate except for the value in benzonitrile, when it is larger than the variation for methyl methacrylate or phenyl methacrylate. The larger variation ofkpfor butyl acrylate is compatible with the view that the origin of the solvent effect lies in complex formation between the propagating radical and aromatic solvent molecules. The exceptional decrease inkpandktin benzonitrile is explained by a contraction of the poly(butyl acrylate) chain in the poor solv

ISSN:0360-6376    

DOI:10.1002/pol.1982.170200610

出版商:John Wiley&Sons, Inc.    

年代:1982

数据来源: WILEY