摘要:

AbstractPlasma‐polymerized oils, films and powders obtained from ethylene, acetylene, butadiene, and benzene were characterized by flash pyrolysis and gas chromatography (P/GC). None of the pyrograms resembled those of commercial polyethylene, polybutadiene, or polystyrene. Each of the plasma‐polymer pyrograms did exhibit essentially the same fragments up to C8, albeit in a different distribution, indicating that all samples are structurally similar. Analysis of the P/GC data shows these materials to contain a random arrangement of side chains, crosslinks, double bonds, and aromatic structures. Changes in the fragment distribution were obvious when the sample was a powder, solid film, or oily film produced from the same monomer. It was shown that powder products generally have a higher concentration of branches and/or crosslinks than the oil or film products. There are also differences in the pyrograms of products of the same form derived from dissimilar monomers. The results obtained from P/GC generally support those derived from infrared or NMR measurements performed earl

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150611

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractThe resolution of 2‐methylproline and the assignment of absolute configuration to the stereoisomer has been carried out. The L‐enantiomer was obtained from the fractional crystallization of the quinine salt of (−)‐N‐carbobenzoxy‐2‐methylproline and the D‐enantiomer from the collected filtrates. The (−)‐2‐methylproline was assigned the L‐configuration by means of the Clough‐Lutz‐Jirgensons method. Polymers were obtained in bulk from theN‐carboxyanhydrides. Although polymers obtained from different solvents exhibited different solubility properties, subsequent spectral studies indicated that this effect was not due to a large conformational change as in the polyproline case. Spectral evidence suggests that poly(2‐methylproline) (P2MP) exists

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150612

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractThe kinetic scheme describing chain transfer in free‐radical polymerizations, the Mayo equation, has been rearranged to yield the probability of generating a functional end group by chain transfer (e.g., to a disulfide). The prediction is that a mixture of functional and nonfunctional ends occurs. Examination of literature data shows a number of systems produce more functionality than predicted. Hence, the challenge to devise a new kinetic scheme to account for the increased functionality is made (e.g., by selective reaction of initiator with chain‐transfer age

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150613

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractHigh molecular weight alternating ethylene–ethyl acrylate copolymers were prepared by using boron trifluoride to complex the acrylate ester. The polymerizations were run under mild conditions (25–50°C, 6–20 atm ethylene) in dichloromethane or dichloroethane solution with free‐radical initiation. At lower ethylene pressures or at less than stoichiometric levels of BF3, the polymers are acrylate‐rich. This is due to ethyl acrylate homopolymerization competing with the copolymerization reaction. The effect of other polymerization variables is also

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150614

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractProperties such as viscosity correlations and spectral data of alternating ethylene–ethyl acrylate copolymers are described. The proton and13C‐NMR spectra show that there is a considerable amount of tacticity in these polymers. Although the alternating configuration predominates, there is also some random structure present. Terpolymers were prepared with cure‐site monomers, such as 2‐chloroethyl acrylate. The terpolymers were compounded with carbon black and cured to give vulcanizates with excellent properties. The cured products are resistant to oil, water, heat, and oxidation. They also have good low temperature properties (stiffening temperature −31°C, brittleness temperature −50°C), tensile properties (tensile strength 17.2 MPa, elongation at break 250%) and compression sets (25% at 150

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150615

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractA series of new polyarylamines was prepared by the vinylogous nuclephilic substitution polymerization of bis(4‐chloro‐3‐nitrophenyl) sulfone with both aromatic and aliphatic diamines. The synthesis involves the solution polycondensation in a polar aprotic solvent at elevated temperatures, a tertiary amine being used as an acid acceptor. Of these solvents, dimethyl sulfoxide andN‐methyl‐2‐pyrrolidone were the most effective for the preparation of high molecular weight polymers. The polyarylamines having inherent viscosities in the range of 0.1–0.5 were all amorphous and highly soluble in polar aprotic solvents. Thermogravimetric analysis under both air and nitrogen atmospheres indicated that rapid decomposition began above 300°C for the polyarylamines from aro

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150616

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractThis paper presents an axiomatic mathematical model for binary copolymerization reactions. The FØRTRAN program entitledMEMØRY3 is described. This program implements the Monte Carlo version of the axiomatic model, computing the most probable sequence distribution. Finally, a concrete copolymerization process is studied and good results are presente

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150617

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

Abstract2‐Hydroxypropyl methacrylate has been copolymerized with methyl acrylate, ethyl acrylate,n‐butyl acrylate, and methyl methacrylate in bulk at 60°C using benzoyl peroxide as initiator. The compositions of copolymers have been determined by the estimation of the hydroxyl group by acetylation process. The copolymerization parameters have been determined by conventional scheme of copolymeriza

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150618

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractPhotodegradation of carbon monoxide–styrene copolymer in benzene was investigated. In relation to the average number of main‐chain scissions per macromolecule versus photoirradiation time, the straight line did not pass through the origin. This phenomenon was attributed to the presence of a labile bond from the carbonyl group in the main chain, in accordance with the results of Cameron and Lawrence which were found in the study of photodegradation of thermally polymerized polystyrene. In utilization of photodegradative behavior in carbon monoxide–styrene copolymer, a block copolymer of styrene with methyl methacrylate was prepared and was ascertained by precipitated fractionation, elementary analysis, and turbidi

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150619

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY

摘要:

AbstractThe effect of the alkyl group on the relative reactivity of a homologous series of vinyl esters (2) has been studied with ethylene (1) as reference monomer,tert‐butyl alcohol as solvent, at 62°C and 35 kg/cm2. The experimental method was based on frequent measurement of the monomer feed composition throughout the copolymerization reaction by means of quantitative gas‐chromatographic analysis. Highly accurate monomer reactivity ratios were estimated in a statistically justified manner by a nonlinear least‐squares method applied to the integrated copolymer equation. The reactivity of the vinyl ester monomers towards an ethylene radical increased with decreasing electron‐with‐drawing ability of the ester group. All vinyl ester radicals considered turned out to have the same preference for their own monomer over ethylene (constantr2= 1.50). Reactivity ratios are discussed in terms of theQ–escheme and the Taft relation. It appeared that chiefly polar factors contribute to the observed relative reactivity, while probably resonance stabilization only plays a minor part. Steric hindrance seems to impair monomer reactivity, only from vinyl pivalate on. Relative reactivities of the vinyl esters are compared with literature values, where other reference monomers ha

ISSN:0360-6376    

DOI:10.1002/pol.1977.170150620

出版商:John Wiley&Sons, Inc.    

年代:1977

数据来源: WILEY