ISSN:0193-7197    

DOI:10.1002/vnl.730100402

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractA study on the melt elasticity behavior and extrudate characteristics of melts of rigid poly(vinyl chloride), PVC, and rigid poly(vinyl chloride)/epoxidized natural rubber (ENR) miscible blends were conducted. Extrusion studies were carried out in a capillary rheometer and examinations of the surface characteristics of the extrudate were made by taking photomicrographs in a scanning electron microscope. The anomalous behavior in the die swell ratio of rigid PVC arising from the particle agglomerates continued in its blends up to 50 wt% composition of ENR. Temperature independence for high ENR blends was noted for the principal normal stress difference and elastic shear modulus, when shear stress was held constant. Recoverable shear strain and die swell ratio behaved identically in terms of blend composition and processing temperature. Factors which control the extrudate distortion and melt fracture of the melts of rigid PVC/ENR systems were fusion of particle agglomerates and strength of melts. Diamond cavitations were typical of the extrudate surface of PVC melts as those of the fracture surface of the tensile failure of PVC. Conditions to obtain a smooth extrudate surface of rigid PVC melts in blends with ENR have been found to be the low ENR content, low shear rate, or stress and high processing temperature.

ISSN:0193-7197    

DOI:10.1002/vnl.730100403

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractInfrared spectroscopy is an important analytical technique for investigating polymeric materials. The physical properties of poly(vinyl chloride) (PVC) depend on its chemical and physical structure. Fourier transform infrared spectroscopy (FTIR) and other infrared techniques are commonly used for studying crystallinity, configurational and conformational changes, and chain orientation in plasticized and non‐plasticized PVC. The C‐Cl stretching region is particularly sensitive to the macromolecular structure and important changes may be detected depending on fundamental paramet

ISSN:0193-7197    

DOI:10.1002/vnl.730100404

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractRecent increased use of ultrafine mechanically ground alumina trehydrate (ATH) as a flame retardant and smoke suppressant has occurred. This growth has, to some extent, displaced the traditional fine precipitated forms of ATH in a variety of polymer applications. In general, the morphology of the more expensive precipitated ATH is different from ground ATH. In this study there appears to be little effect of ATH particle morphology on the PVC performance properties tested.

ISSN:0193-7197    

DOI:10.1002/vnl.730100405

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractPrevious studies of PVC with styrene/maleic anhydride (SMAnh) copolymers showed miscibility or single phase morphology, but only at very low blended proportions of 10:1. At higher blend proportions this alloy system separated into two altered phases, neither being a pure component. Unlike PVC/SMAnh alloys, chlorinated poly(vinyl chloride) (CPVC) SMAnh systems show total miscibility for all blended proportions. The effects of alloying CPVC resins with SMAnh copolymers is the subject of this report. Using DSC and DMA miscibility of these systems are examined. Effects of SMAnh levels in these alloys on heat resistance, melt viscosity, processability, and flame retardance are assessed.

ISSN:0193-7197    

DOI:10.1002/vnl.730100406

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough polymer/polymer miscibility is considered the exception to the general rule, in polymer thermodynamics specific interactions between active sites on two polymers can be a driving force for polymer/polymer miscibility. Both the intermolecular interactions of the alpha hydrogen of PVC with carbonyl groups in various polyesters and the polarity of the chlorine bond have been claimed to promote miscibility. Both of these interactions are potential in PVC/styrene maleic anhydride (SMAnh) polymer blends. These specific interactions promoting miscibility and the resulting mechanical properties of these systems is the subject of this report. SMAnh (12.5% MA) copolymer was melt compounded with a stabilized PVC compound using a Haake Rheocord twin screw extruder. Test data generated for these blends were analyzed for miscibility and effects of SMAnh copolymers on heat resistance, fire retardance, impact strength, and processability of PVC.

ISSN:0193-7197    

DOI:10.1002/vnl.730100407

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractShrinkage in PVC profile extrusions may have an effect on the end use performance (dimensional stability, mechanical properties) of the building products such as house siding and windows when they are heated by the sun. This paper examines the heat shrinkage tests being used in the industry, and most importantly, describes effects of the extrusion conditions such as melt temperature, shear rate, percent drawdown, and other variables on shrinkage in PVC profiles.

ISSN:0193-7197    

DOI:10.1002/vnl.730100408

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractA problem encountered in the instrumental evaluation of color is the use of integrating sphere spectrophotometers to compare materials where the standard color plaque is not constructed from the same material as the sample. This problem is encountered in the automobile industry, where polypropylene master plaques are commonly used as the standards constructed from different materials than the sample being evaluated. The paper demonstrates how these problems result from the impact of a polymer's refractive index on the reflectivity of light from its surface, and the effect of this light on the instrumental evaluations of color. The paper also discusses how the Fresnel equation can be utilized to calculate the amount of light reflected from a polymer's surface and describes a mathematical procedure that can help compensate for these differences when matching and approving colors.

ISSN:0193-7197    

DOI:10.1002/vnl.730100409

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractIn an attempt to better understand factors that govern the fracture resistance of rigid vinyl components, a multifaceted study was undertaken. Fracture toughness was determined by a high rate servohydraulic tester. Failure morphologies were analyzed by Scanning Electron Microscopy (SEM). In many cases, very abrupt ductile to brittle transitions were observed at moderate strain rates. In addition, since the glass transition temperature for these materials are relatively low, being of the order of 70°C to 80°C, considerable free volume relaxation or physical aging are observed at conditions near or slightly above ambient. Differential Scanning Calorimetry (DSC) was used to quantify the degree of aging. Results correlated with observed failure propertie

ISSN:0193-7197    

DOI:10.1002/vnl.730100410

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

ISSN:0193-7197    

DOI:10.1002/vnl.730100401

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY