摘要:

The amination reactions of chloromethylated polystyrene withN,N-dimethyldodecylamine,N,N-dimethyltetradecylamine, andN,N-dimethylhexadecylamine were studied. The physical properties, particularly the solubility properties of the resulting polymers, are influenced by the hydrophobic properties of the long alkyl chain on the N+atoms. The main factor that influences the kinetics of the reactions is the polymersolvent interaction parameter.

ISSN:0022-233X    

DOI:10.1080/00222338808053373

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Viscosity measurements of cellulose acetate and polyisobutylene over a wide range of concentrations and molecular weights have been made. The data so obtained and the data taken from the literature for schizophyllan show that the viscosity varies smoothly with concentration of the polymer for the whole range of concentrations and molecular weights investigated. The characteristic concentrations,Cch, of the polymers are calculated by the following equations:Cch= 0.77/[η] orCch= 1.08/[η]. The relationship between molecular weight and intrinsic viscosity is obtained by fitting the data by the method of least squares. By plotting the reduced viscosity versus the reduced concentration, superposition curves are obtained for both cellulose acetate and polyisobutylene. It is not possible to obtain superposition curves for schizophyllan, which is a more rigid polymer.

ISSN:0022-233X    

DOI:10.1080/00222338808053374

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Glow-discharge-initiated polymerization of acrylic acid incorporated in poly(ethylene terephthalate) (PET) films was investigated. An increase in polymerization yield with plasma treatment duration and power was found. Polymerization was not confined to the film surface. At high power and long treatment time, polymerization in the bulk of the PET also took place. Water regain and contact angle of the PET-treated films were affected by the presence of poly(acrylic acid) (PAA). The carboxyl groups of the PAA chains incorporated in the PET matrix were utilized for further chemical modification of the PET film. Poly(ethylene glycol) (PEG) was grafted onto PAA by esterification. DSC studies showed the presence of both PAA and PEG in the PET matrix and shed light on the morphology of the multicomponent polymeric system. Free isocyanate groups were introduced into the PET matrix by reacting PAA carboxyl groups with hexamethylene diisocyanate.

ISSN:0022-233X    

DOI:10.1080/00222338808053375

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

New amphiphilic networks have been synthesized by free-radical co-polymerization of hydrophobic methacryloyl-capped polyisobutylenes (MA-PIB-MA) with hydrophilic 2-(dimethylamino)ethyl methacrylate. Two MA-PIB-MAs have been prepared withMn= 4920 and 10 200, and two series of networks were prepared with MA-PIB-MA contents between 48 and 71.5%. Variation of the molecular weight of MA-PIB-MA and its concentration in the network allows for a wide range of mechanical properties and swellability in hydrophilic and hydrophobic solvents. Differential scanning calorimetry shows the existence of two glass transitions in these networks and thus indicates a phase-separated domain structure. Tensile strengths and elongations were dependent on MA-PIB-MA contents varying from 57.7 to 39.8 kg/cm2and from 168 to 200%, respectively, with increasing MA-PIB-MA content. Solvent swelling of the networks ranged from 170 to 20% in water and from 40 to 170% inn-heptane with increasing MA-PIB-MA contents.

ISSN:0022-233X    

DOI:10.1080/00222338808053376

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

ISSN:0022-233X    

DOI:10.1080/00222338808053377

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Various types of halogen-terminated polymers having different backbones were synthesized and used as polymeric initiators together with manganese carbonyl for block polymerizations. The number of end groups and the molecular weights of the polymeric initiators could be varied by adjusting the feed composition and the transfer agent. Block polymerizations of methyl methacrylate and styrene with these telechelic bromo-terminated polymers-manganese carbonyl initiator systems were carried out photochemically at 30°C and in the dark at 80°C. It was found that the dark polymerization with the initiator system at 80°C provided excellent conditions to control the length of the blocks. Polymerization of methyl methacrylate initiated by manganese carbonyl together with carbon tetrabromide as a model compound of the polymeric initiator was also investigated. Block-forming efficiencies of these block polymerizations were estimated to range from 96 to 99%. The number-average degree of polymerization of blocks of the second monomer obtained by use of the telechelic bromo-terminated backbone polymer as polymeric initiator could be controlled by adjusting the amount of the second monomers and the polymeric initiator/manganese carbonyl ratio.

ISSN:0022-233X    

DOI:10.1080/00222338808053378

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Three block copolymers of poly(ethylene succinate) and poly(tetramethylene glycol) with about 20, 54, and 59 mol% polyether have been prepared and subjected to hydrolytic degradation at 37°C. The sample containing 59 mol% showed drastic changes in the properties after 3 months of degradation, whereas the other samples exhibited only minor changes. The tensile strength was completely lost, the molecular weight had decreased to 7% of the original value, and the crystallinity (measured as heat of fusion) had more than doubled. IR and1H-NMR analyses showed that the rates of release of the different polymeric blocks varied throughout the period of hydrolytic degradation. Fibers of the block copolymer poly(ethylene succinate)/poly(tetramethylene glycol) with poly(tetramethylene glycol) fractions ranging from 20 to 50 mol% have been analyzed by13C NMR to determine the molecular weights of the PES blocks and by reflection IR, ESCA, and SEM to investigate the surface composition. The molecular weights of the polyester blocks were inversely proportional to the mol% of polyether, and the values were in agreement with theoretical calculated values. The surface concentration of the polyether was found to be higher than that in the bulk and also independent of the mol% polyether in the range of study. A degradation mechanism is proposed which involves a combined effect of surface erosion and hydrolytic attack on the ester linkages connecting the amorphous polyether and the crystalline polyester blocks.

ISSN:0022-233X    

DOI:10.1080/00222338808053379

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This is a scanned image of the original Editorial Board page(s) for this issue.

ISSN:0022-233X    

DOI:10.1080/00222338808053372

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor