摘要:

AbstractPreviously, it was found that organic glass material having no optical strain could be cast efficiently in a very short time by radiation‐induced cast polymerization of glass‐forming monomers. In this report, practical useful monomer systems having glass‐forming property and good physical properties were investigated. Several inner plasticized comonomer systems of excellent impact resistance were found which could be glassified and applied to radiation casting. These systems included butyl acrylate or hexanediol monoacrylate as inner plasticized component. Physical properties other than impact resistance were tested. The casting polymerization was studied, and it was found that polymers without optical strain could be obtained in a remarkably short

ISSN:0021-8995    

DOI:10.1002/app.1978.070220101

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe applicability to radiation‐induced cast polymerization of polyfunctional monomers or systems including them was studied. Most of polyfunctional monomers could be glassified and were applicable to radiation casting. The effect of tetraethylene glycol diacrylate on inner‐plasticized comonomer systems was studied in detail. It was found that the glass‐forming property increased by the addition of tetraethylene glycol diacrylate and that heat durability improved satisfactorily. The formation of optical strain in casting was relatively easier in polyfunctional monomers including systems due to inner stress, although the merit of radiation casting was still ob

ISSN:0021-8995    

DOI:10.1002/app.1978.070220102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractGlassification, cast polymerization, and physical properties of monomeric system including diethylene‐glycolbisallyl carbonate (CR‐39) was investigated. Addition of other monomers CR‐39 was investigated CR39‐ polyfunctional monomer and CR‐39‐methyl methacrylate‐polyfunctional monomer systems were found to form stable glassy state applicable to radiation‐induced casting and good in physical property. Two‐step polymerization method consisting of pre‐irradiation and post‐catalytic polymerization necessary to complete casting. It was found that these newly found CR‐39 modified systems could be casted efficiently in much shorter time cycle than catalytic process without forming optical strain. Physical properties of casted polymer such as impact resistance and heat durability were suffi

ISSN:0021-8995    

DOI:10.1002/app.1978.070220103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractCasting of methyl methacrylate prepolymer by irradiation at relatively low temperatures was studied. It was difficult to completely glassify the methyl methacrylate monomer and prepolymer, and so the casting was carried out at temperatures above its melting point (−48°C). The optical strain formed in this stream remained of the stress type, and optical strain formation was reduced with increasing prepolymer concentration and decreasing temperatu

ISSN:0021-8995    

DOI:10.1002/app.1978.070220104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThis paper reports the synthesis, characterization, and evaluation of copolymers of methyl methacrylate (MMA) and hexyl methacrylate (HMA) and of HMA and methyl α‐chloroacrylate (MCA) and of terpolymers of MMA, MCA, and HMA as electron‐sensitive positive resists. The sensitivities of the resists were found to be strongly dependent on the composition. Two of the terpolymers were found to be significantly more sensitive than poly(methyl methacrylate) (P

ISSN:0021-8995    

DOI:10.1002/app.1978.070220105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractAn accelerating potential of 75 kV combined with very low beam current and exposure time of 5 sec seem ideal for recording electron diffraction pattern of cooled specimens of cellulose microfibrils. Over 16 reflections could be seen distinctly. The structural parameters of ordered regions were: 89% crystallinity index, 72 Å crystallite width, and 209–230 Å crystallite length. Even the diffraction pattern of the uncooled specimen at 75 kV had a large number of reflections and was superior to those recorded on the cooled specimen at 50 or 100

ISSN:0021-8995    

DOI:10.1002/app.1978.070220106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe use of electropolymerization to coat metal electrode surfaces with polymers formedin situwas investigated in detail. Electrolysis was carried out in a three‐compartment cell with fritted disk separators such that polymerization occurred in the middle compartment only. Both anodic and cathodic reactions were utilized to form coating on pretreated metal surfaces. It was shown that polymerization occurred both by vinyl polymerization of olefin monomers as well as by ring‐opening reactions of cyclic monomers. The factors that control the coating thickness, the morphology of the polymer deposit, and the adhesion of the polymer formed to the metal substrates were determined. It was found that the growth of the coating on electrode followed the chain polymerization kinetics to a considerable degree. However, increased current did not necessarily lead to increased coating thickness because it also led to increased early termination of growing polymer chains to form soluble low molecular weight products. Water, because of its high surface tension, encourages physical adsorption on metal surfaces of organic monomers dissolved in it. Thus, water was found to be unique as solvent for obtaining coatings with good adhesion to metal substrates. Coatings formed were analyzed by several methods including infrared spectroscopy. Several types of bonding, other than bond formation caused by polymerization reactions, were identified. Finally, the cyclization of polyacrylonitrile was observed when the coating was obtained on aluminum cathode during electrolysis of acrylonitrile–sodium nitrate–DMF s

ISSN:0021-8995    

DOI:10.1002/app.1978.070220107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractA computational algorithm for the detailed simulation of a batch emulsion polymerization reactor is discussed. The model is applied to the polymerization of methyl methacrylate, and the model predictions are shown to be in good agreement with experimental data. Further computations show the influence of reactor operating conditions on the polymer product and the reactor performance.

ISSN:0021-8995    

DOI:10.1002/app.1978.070220108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractUsing derivative thermogravimetric analysis (DTG), polybutadiene is shown to degrade by two distinct weight loss events when heated dynamically. The volatile products of the first stage are almost exclusively depolymerization products (butadiene and vinylcyclohexene). The residue—cyclized and crosslinked polybutadiene—degrades in the second stage. Increasing the heating rate or sample size results in increased depolymerization; and at a 100°C/min heating rate, up to 50% of the initial sample weight is converted to depolymerization products. Differential scanning calorimetry (DSC) indicates that degradation is exothermic in the temperature range of the first weight loss stage. The determined exothermicity (0.95 kJ/g polybutadiene) is independent of heating rate. Infrared observations showcis—transisomerization in the same temperature range. Kinetic analysis of the DTG data yields an apparent activation energy of 251 kJ/mole for depolymerization, while for the overall reactions is the first stage, DSC data yield 170 kJ/mole. Why the exothermicity of the degradation is independent of the depolymerization/cyclization ratio is not

ISSN:0021-8995    

DOI:10.1002/app.1978.070220109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effects of a pretreatment of polyester (PET) yarns with a strongly interacting solvent such as dimethylformamide (DMF) on vinyl monomer incorporation were investigated. When the DMF pretreatment is carried out at high temperatures (above 120°C), the swollen PET structure is stabilized by solvent‐induced secondary crystallization. This substrate is highly suitable for the incorporation of vinyl monomers.In situpolymerization of vinyl monomers in DMF‐treated PET was investigated using chemical and γ‐irradiation polymerization techniques, both in the presence and in the absence of excess monomer outside the PET fibers. When polymerization was carried out in a system in which a constant supply of free radicals was available from the outside of the PET fibers, lower initiator concentrations and smaller γ‐irradiation doses were necessary. These results are attributed to a low efficiency of the initiator inside the PET fiber due to mobility restrictions. Water uptake and moisture regain of PET yarns containing poly(hydroxyethyl methacrylate) and poly(acrylic acid) were also investigated. When most of the vinyl polymer was inside the PET fiber, water absorption was limited. The changes in mechanical properties of the PET yarns resulting from the DMF pretreatment were partially reversed byin situpolymerization of viny

ISSN:0021-8995    

DOI:10.1002/app.1978.070220110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1978

数据来源: WILEY