摘要:

AbstractWe compared the cross‐polymerization of diacetylene units, incorporated in different ways into polyamide (PA) matrices: as fragments of the PA main chains (PA1) and as pendant groups of the PA main chains (PA2). At room temperature the reaction proceeds only in PA1 via 1,4‐addition (cross‐links I). However at high temperature besides of cross‐links I another type of cross‐links (cross‐links II) is formed, presumably via 1,2‐addition reaction. In PA2 only cross‐links of type II are formed at hi

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160301

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe mesophase behaviour of liquid‐crystalline polymethacrylates with 4′‐trifluoromethoxyazobenzene mesogens and alkylene spacers\documentclass{article}\pagestyle{empty}\begin{document}$ \left( {\rlap{--} ({\rm CH}_{\rm 2} \rlap{--} )_n ,n = 2 - 6} \right) $\end{document}in the side chains was investigated and compared with that of the corresponding non‐fluorinated polymers. The fluorinated polymers with spacer lengthsn= 5 and 6 are the first side‐group liquid‐crystalline polymethacrylates showing a nematic phase below a smec

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160302

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractPolymerization of 1,3‐butadiene with the CoBr2(PPh3)2/MgCl2/SiPh2(OCH3)2‐Al(CH3)3catalyst system was conducted in the presence of ethylene. It was found that addition of ethylene causes a marked decrease in the molecular weight of polybutadiene although ethylene is not incorporated at the chain‐end. The structure of chain‐ends was analyzed using very low molecular‐weight polybutadiene produced in the presence of ethylene, which led to the conclusion that 1,2 and 2,1 insertion reactions predominate at the initiation and propagation steps, res

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160303

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractGraft copolymers of poly(N‐isopropylacrylamide) (PNIPAAm) on a poly(acrylic acid) backbone retain the temperature‐induced phase transition behavior of PNIPAAm over a wide range of compositions even at pH 7,4 and should be useful for sustained‐release, bioadhesive drug delivery systems at physiologic condi

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160304

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160305

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe structural features of poly[bis(4‐isopropylphenoxy)phosphazene] (PB(4‐ip)PP) have been studied by electron microscopy, X‐ray diffraction and differential scanning calorimetry techniques. Its orthorhombic lattice constants are determined as follows:a= 3,14 nm,b= 1,14 nm,c= 0,992 nm. The space group of this polymer is suggested to beP212121–D 24, and the molecular conformation of the chains possibly to be (trans3cis)2. This polymer exhibits a crystal/crystal transition at 86°C below itsT(1) transition (120°C). The thermal behavior is similar to the characteristics of poly[bis(p‐methoxyphenoxy

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160306

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractKnowledge of polymer‐polymer interactions is employed to design an improved media for dye diffusion thermal transfer (D2T2). Selecting the donor and receiver sheet binder polymers to be an immiscible pair results in acceptable images free from the “sticking” during printing that is observed if these two polymers are miscible. This approach has the potential to improve upon the dye density and surface characteristics of current commercial sy

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160307

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractThe anionic polymerization of 2‐oxetanone and 4‐methyl‐2‐oxetanone initiated with the potassium hydride/18‐crown‐6 complex was investigated. The α‐proton abstraction of the monomer was found to proceed at the initiation step of this polymerization. The salt of the unsaturated carboxylic acid formed initiates further propagation, leading to functionalized polyesters with unsaturated, d

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160308

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractExtension of the Mayo‐Lewis Model of copolymerization concerning solvent effects in free‐radical polymerization is discussed on the basis of the bootstrap and penultimate unit effe

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160309

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY

摘要:

AbstractIn this paper we describe a method for the functionalization of catenapoly[bis(4‐hydroxyphenoxy)‐λ5‐phosphazene] with diazonium salts to form new, deeply‐coloured, phosphazene copolymers containing variable amounts of azo dyes attached to the polyphosphazene skeleton. The degree of functionalization in these substrates is regulated in order not to exceed 20% of the sites available in the pristine polyphosphazene and to maintain a high percentage of unreacted, free, hydroxy groups, in the final, coloured copolymers. These species are still very reactive and able to undergo further functionalization r

ISSN:1022-1336    

DOI:10.1002/marc.1995.030160310

出版商:Hüthig&Wepf Verlag    

年代:1995

数据来源: WILEY