ISSN:0193-7197    

DOI:10.1002/vnl.730120102

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractThe inherent viscosity of PVC resin in compounds containing fillers and additives can be calculated accurately and conveniently from the weight average molecular weight or the peak molecular weight as measured by High Performance‐Size Exclusion Chromatography (HP‐SEC). Molecular weight/inherent viscosity relationships are shown for typical production PVC resins. The utility of HP‐SEC instrumentation for the determination of IV for samples of commercial interest is demonstrated. Mark‐Houwink coefficients from the literature were used to calculate a convenient conversion factor of 0.612, which can be used to convert the molecular weight measured relative to polystyrene by HP‐SEC to the actual molecular weigh

ISSN:0193-7197    

DOI:10.1002/vnl.730120103

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractBased on the analysis of a simple mathematical model, different temperature profiles are generated in order to provide vinyl chloride (VCM) suspension polymerization with constant reaction rates in batch reactors. In order to reproduce these temperature profiles in industrial‐scale reactors, some process variables, such as coolant temperature, initiator concentration, and rate of water and monomer condensation, have to be manipulated. It is shown that those temperature practices can almost never be applied to large‐scale reactors if the jacket temperature is the only variable that can be manipulated. It is also shown that developing an initiator feed procedure or using a reflux condenser may be advantage

ISSN:0193-7197    

DOI:10.1002/vnl.730120104

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractUnder study were the mechanical properties of particle boards comprised of ground sugarcane bagasse, PVC, and poly{methylene (polyphenyl isocyanate)} [PMPPIC]. The effects of different parameters, e.g. mixing temperature, molding conditions ‐ platen temperature, time and pressure, particle size of bagasse, concentration of PVC and PMPPIC, as well as dilution of PMPPIC, on the mechanical properties of the resulting particle boards were also investigated. In general, the properties of particle boards change with the variation of mixing and molding conditions. A mixing temperature of 175°C and molding conditions [platen temperature, 190°C; time, 10 min; and pressure, 3.8 MPa]were believed to be optimal conditions of compounding particle boards. Both the mechanical properties and the density of particle boards of bagasse with a mesh size of 60, improved up to 20 weight % of PVC and 10 weight % of PMP

ISSN:0193-7197    

DOI:10.1002/vnl.730120105

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractIt is known that oxidation occurring during processing of some polymers like PVC and polypropylene causes their deterioration. This, in turn, detracts from its service life. This study shows how the extrusion process shear can be detected and followed stepwise and in effect be controlled. Separate identification of fragmentation and crosslinking levels are determined. Quantification of shearing, fragmentation, and crosslinking of the PVC melt is used to derive service life loss due to extrusion processing.

ISSN:0193-7197    

DOI:10.1002/vnl.730120106

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractMatte finishes are characterized by a lack of specular (mirror‐like) reflectance. Using equations from the literature which relate surface roughness to specular reflectance, surface roughness values were calculated for various particle size inclusions assuming that the particles protruded half in half out of the surface and that 20% of the surface area is covered by the particles. Specular reflectance values at 85 deg illumination were calculated from the surface roughness calculated data. Based on these calculations, a series of large particle size monodispersed emulsion polymers was prepared using Ugelatad polymerization techniques and evaluated for their surface altering effects in PVC. Considering that the model contained many approximations, excellent agreement was found between the predicted and measured particle size effect on the surface glos

ISSN:0193-7197    

DOI:10.1002/vnl.730120107

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractAn allylic model compound for degrading PVC, cinnamyl chloride, was found to react with metal carboxylates in n‐butyl acetate at 50°C with rates first order in each component. The corresponding metal chlorides and a mixture of rearranged and unrearranged allyl esters were isolated. With cadmium carboxylates, the rate constant is of the order of 300 × 10−5sec−1; with barium carboxylates, two orders of magnitude slower. In the presence of excess barium carboxylate, the rate of reaction is first order in cadmium and independent of barium concentration; the product is, however, barium chloride. Under such conditions, only unrearranged allyl ester is recovered. These observations are interpreted in terms of a rapid step leading to formation of a carboxylate‐bridged barium/cadmium intermediate. It is proposed that such intermediates displace chloride from allylic carbon by a concerted mechanism, generating chloride‐bridged reaction products that collapse exclusively to bari

ISSN:0193-7197    

DOI:10.1002/vnl.730120108

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractPresent testing methods of comparing dryblend and fusion characteristics of poly (vinyl chloride) address resin interchange, but not plasticizer interchange. The wide range of available plasticizers requires methodology to predict plasticizer performance from a processing viewpoint. Modification of the test parameters reported in this study makes it possible to predict how plasticizer interchange affects processing under dynamic conditions.

ISSN:0193-7197    

DOI:10.1002/vnl.730120109

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractExtrusion products that to not meet specification are generally reground for extrusion reprocessing. This paper describes the effect of heat history of regrind materials on extrusion quality, including surface appearance (melt fracture), toughness, edge tear, and heat stability. It is hoped that the information presented in this paper will help processors optimize use of regrind for best performance.

ISSN:0193-7197    

DOI:10.1002/vnl.730120110

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY

摘要:

AbstractVinyl is used in a wide range of applications, not only in packaging but also in construction, automotive, and other areas. Vinyl (polyvinyl chloride, or PVC) has maintained a significant presence in some markets for more than 30 years. Yet vinyl is not necessarily on the downward leg of its product life cycle. New, more effective PVC blow molding compounds are being developed and introduced. These versatile new polymers are extending the life cycle of vinyl packaging into the 21st century. The long‐standing success of vinyl in bottle applications is due to a number of key properties, including its chemical resistance, UV stability, low mold costs, design flexibility, low permeability, and aesthetics. In recent years, improved PVC compounds have created new growth markets for vinyl. Three important ones are hot‐fill applications, personal care products, and bottled water. The potential of vinyl bottles to become a major factor in the fast‐growing bottled water market is a particularly good example of the adaptability and versatility that make vinyl one of the most exciting “new” blow molding

ISSN:0193-7197    

DOI:10.1002/vnl.730120111

出版商:Society of Plastics Engineers    

年代:1990

数据来源: WILEY