摘要:

AbstractThe solubility of vinyl chloride (VCM) vapor in poly (vinyl chloride) (PVC) in a water slurry has been measured between 55 and 65°C. The heat and entropy of sorption were shown to be very close to those of condensation. The solubilities measured in this study were higher than those obtained in other studies on dry PVC and PVC latex. The interaction parameter (x) in the Flory‐Huggins equation has been shown to vary between 0.34 and 0.61 over the composition range studied. The effect of ageing the slurry in the presence of VCM is also discuss

ISSN:0032-3888    

DOI:10.1002/pen.760181102

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractHeating of isocyanate derived foams with glycol mixtures is a simple and economically attractive recycling process. The process is emission free, not sensitive to varying product mixes and the obtained polyols can be completely reused in the manufacture of rigid polyurethane or polyisocyanurate foam.

ISSN:0032-3888    

DOI:10.1002/pen.760181103

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractAn experimental study was carried out to investigate the effects of titanate coupling agents on the rheological properties of p articulate‐filled polyolefin melts. Inorganic fillers used were CaCO3, talc, and fiberglass, and polyolefins used were high‐density polyethylene (HOPE) and polypropylene (PP). It was found that the addition of the coupling agent TTS to the PP‐CaCO3and PP‐fiberglass systems reduced the melt viscosity considerably, whereas the addition of the coupling agent ETDS‐201 to the PP‐talc and HDPE‐talc systems affected the melt viscosity very little. Also carried out was an injection molding study to investigate the effects of different inorganic fillers and the titanate coupling agents used on the mechanical properties of the injection molded specimens. It was found that addition of titanate coupling agents generally resulted in reduced modulus and tensile strength, and increased elongation and impact strength of the filled systems. The PP‐CaCO3‐TTS and HDPE‐talc‐ETDS 201 systems were found to have impact strength improved by approximately 100 percent with the addition of a titanate coupling agent. The PP‐CaCO3‐TTS samples have ultimate tensile elongation appr

ISSN:0032-3888    

DOI:10.1002/pen.760181104

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe thermochemical and flammability characteristics of some typical thermoplastic materials currently in use and others being considered for use in aircraft interiors are described. The properties studied included (a) thermal mechanical properties such as glass transition and melt temperature, (b) changes in polymer enthalpy by differential scanning calorimetry, (c) thermogravimetric analysis in an anaerobic and oxidative environment, (d) oxygen index, (e) smoke evolution, (f) relative toxicity of the volatile products of pyrolysis, and (g) selected physical properties. The generic polymers which were evaluated included: acrylonitrile‐butadiene‐styrene, bisphenol A polycarbonate, bisphenol fluorenone carbonate‐dimethylsiloxane block polymer, phenolphthalein‐bisphenol A polycarbonate, phenolphthalein polycarbonate, polyelher sulfone, polyphenylene oxide, polyphenylene sulfide, polyaryl sulfone; chlorinated poly vinyl chloride homopolymer, polyvinyl fluoride, and polyvinylidene fluoride. Processing parameters including molding characteristics of some of the advanced polymers are described. Test results and relative rankings of some of the flam inability, smoke and toxicity properties are presented. Under these test conditions, some of the advanced polymers evaluated were significantly less flammable and toxic or equivalent to polymers in current use. A relationship of the anaerobic char yield of the polymers to their relative flammability properties i

ISSN:0032-3888    

DOI:10.1002/pen.760181105

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractUltraoriented films of high density polyethylene (HDPE) have been prepared in continuous lengths by a new method, solid state coextrusion, through conical dies of extrusion draw ratios up to 36. Preformed HDPE billets ∽7 cm long and ∽1 cm in diameter of duPont Alathon 7050R,Mw= 59,000,Mn= 19,900, were split longitudinally into halves and then one or more wafers of the same polymer were inserted between the two sheath halves. Thereafter, the whole assembly was extruded through a conical die of 20° included entrance angle in the absence of lubricant and at temperatures substantially below the melting range yielding continuous and transparent films. The physical and mechanical properties of the HDPE films so produced were evaluated and compared with the properties of the same polymer extruded through a slit die. The high melt transition, tensile modulus and transparency confirm the effectiveness of the new method in continuously attaining ultradrawn f

ISSN:0032-3888    

DOI:10.1002/pen.760181106

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractPrevious studies by a gravimetric technique have established that the sorption and desorption of small quantities of vinyl chloride monomer (VCM) by poly (vinyl chloride) (PVC) resin powders obeys Fickian diffusion kinetics. Consequently, the rate of sorption or desorption is very sensitive to the size and structure distribution of the resin particles and is a useful measure of these properties. To facilitate the measurement of desorption rates, an “inverse GC” technique has been developed, with the PVC powder taking the place of the usual gas Chromatograph column. The detector and electronics of the GC are used to follow the VCM content of a carrier gas stream passing through a PVC resin sample initially equilibrated to a uniform VCM content. This method yields results consistent with the gravimetric data and provides a convenient means of characterizing PVC particle struct

ISSN:0032-3888    

DOI:10.1002/pen.760181107

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe effect of time of indentation and time of recovery on the Rockwell hardness, of a series of glassy and crystalline polymers has been determined. An analytical technique, based on conventional viscoelastic approaches, has been developed. This technique permits the resolution of the hardness number into its components of permanent deformation, retarded elastic compression, and retarded elastic recovery. Subtraction of components due to retarded elastic response results in hardness numbers dependent only the time‐dependent permanent deformation. Extrapolation of this data to zero time results in an absolute or time‐independent value of Rockwell hardness, designate

ISSN:0032-3888    

DOI:10.1002/pen.760181108

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractThe rheological behavior of a sample of H‐H polystyrene ofMnof 41,000 and aMw/Mnof 2 was compared at 160 and 190°C with a sample of H‐T atactic polystyrene of similar molecular weight. The melt viscosity of H‐H polymer (unlike the H‐T polymer) was non‐Newtonian at low stresses and decreased more rapidly with stress. This observation seems to indicate a stiffer polymer chain for the H‐H polystyrene. The flow activation energy (E*) of H‐H polystyrene was found to be dependent on the dynamic shear stress and decreased with increasing dynamic shear stress. The dynamic shear storage modulus of the H‐H polymer has a smaller increase ofG′ with ω than that of

ISSN:0032-3888    

DOI:10.1002/pen.760181109

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractAnnular hot runner systems, in which the inner surface is heated and the outer surface cooled, are being used increasingly in the injection molding of thermoplastics. In this paper a computer model which has been developed to calculate transient pressure, temperature, and velocity fields is described. Using the properties of acrylonitrile‐butadiene‐styrene for illustration, some detailed temperature and velocity profiles computed with the model are presented for atypical hot runner section. The effects of a number of design and operating variables on the pressure drop are also presen

ISSN:0032-3888    

DOI:10.1002/pen.760181110

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY

摘要:

AbstractPoly (alpha‐methylstyrene) (PAMS) is a new approach to process improvement in rigid poly (vinyl chloride) (PVC)—the use of a low molecular weight polymer as a process aid. PAMS can reduce fusion time, melt viscosity and improve heat stability of rigid PVC compounds. The reduced melt viscosity allows the addition of fillers to PVC without adverse effect on extrusion rates. This polymer also improves the resistance to melt fracture and shear “burning” at high shear rates. When used within the optimum concentration range, physical properties such as tensile strength, Izod impact and heat distortion are maintained. In addition, PAMS gives, improved production rates in both pipe extrusion and injection molding processes without sacrifice in pro

ISSN:0032-3888    

DOI:10.1002/pen.760181111

出版商:Society of Plastics Engineers, Inc.    

年代:1978

数据来源: WILEY