ISSN:0193-7197    

DOI:10.1002/vnl.730100102

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractPlasticized polyvinyl chloride will be attacked by microorganisms. The microorganisms will use the plasticizer as a carbon source, whereas favorable growth conditions, like water and oxygen, promotes their growth.A clear effect of the temperature of the water used in leaching experiments on the rate of fungal growth on the foil surface could be demonstrated. Studies also showed a difference in susceptibility of several types of plasticizers to fungal attack. The plasticizers can be divided into several classes based on their susceptibility to fungal attack.Detailed studies on the microbiological population on foil surfaces showed the predominating position of fungi. This indicated a metabiotic system between fungi and bacteria on foil surface. Addition of biocides, during manufacturing of PVC, primarily must have fungistatic properties. The fungistatic activity of 10,10′‐oxybisphenoxyarsine (OBPA) is very high, and in consequence, very low concentration must be available on foil surfaces which will prevent fungal growth. These low amounts on foil surfaces are directly correlated to the amount of OBPA insite of the foil. The transport process of the insite OBPA to the surface of the foil will principally be determined by the recepe of the foil. Therefore the application concentration recommended to ensure to achieve the minimum inhibitory concentration for fungi on the foil surface will be determined from where the application actually manifests its

ISSN:0193-7197    

DOI:10.1002/vnl.730100103

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe surface IR absorption characteristics of MBS impact modified and unmodified PVC specimens prepared in various ways were determined by ATR‐FTIR techniques. These specimens include compression molded plaques and blow molded bottles. In addition and as a reference point, the IR spectrum of a solution cast film of unmodified PVC was obtained in the transmission mode. The IR spectra in the C‐Cl stretching region for unmodified plaques, i.e. 560 to 750 cm−1, were curve fitted to seven Lorenz functions centered at the literature frequencies, except for one band which was changed from 639 to 636.5 cm−1. Two additional bands (699 and 759 cm−1) were assumed to represent the modifier absorption in modified plaques and bottles. Only peak intensities and band widths were allowed to vary in the curve fitting process. Deconvoluted spectra of selected specimens support the number and location of the absorption peaks.Though these surface spectral changes can be represented in terms of surface configurational partitioning that occurred during processing, a more likely explanation is that conformational changes in the PVC polymer chain has occurred on the surface. Quantities representing the configuration of PVC polymer chains such as non‐syndiotacticity (NSS) or the fraction of PVC backbone carbon atoms that are found in the trans conformation (TRANS) were estimated from Lorenz parameters. NSS and TRANS were found to depend on processing conditions as well as the nature of the modifier.These results are discussed in terms of practical impact tests such as n‐Izod and falling bott

ISSN:0193-7197    

DOI:10.1002/vnl.730100104

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractDimensional stability problems such as warpage, bowing and other changes in shape and size may occur when exterior building products (siding, windows) are heated by the sun. This paper describes the effects of material properties such as coefficient of thermal expansion, heat distortion temperature, modulus, and heat build‐up, caused by the sun, on dimensional stability of the exterior building product

ISSN:0193-7197    

DOI:10.1002/vnl.730100105

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractPolyvinyl chloride has been commercial for about fifty years. However, PVC is generally not thought of as an engineering thermoplastic. However, PVC can be engineered into many applications based on predictable engineering performance. PVC engineering data is presented.

ISSN:0193-7197    

DOI:10.1002/vnl.730100106

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractAlthough plastics have made significant inroads in the packaging area, little work has been done in the U.S. to evaluate their effect on the taste and odor of the package contents. This is especially relevant for food, beverage, liquor, and bottled water.Rohm and Haas contracted with an independent consulting firm, which uses a professional panel familiar with the effects of packaging, to assess the sensory impact of different plastics on the taste of water. Four types of plastics were tested: polyvinyl chloride (PVC), high‐density polyethylene (HDPE), polycarbonate (PC), and polyethylene terephthalate (PET).Two forms of each polymer were evaluated, bottles and plaques, which were aged in water for four weeks at room and elevated temperature (120°F). The professional panel evaluated the taste and odor of the water on a numerical intensity scale and characterized any observed effect with words. The numerical rating permitted the effects of the plastic materials to be compared directly.PVC had the lowest contribution to taste and odor of all of the plastics. PVC was followed by PET and then PC and HDPE. Therefore the two current packaging materials, HDPE and PC, were not the best! This implies that water and other taste‐sensitive products could be more appealing if packaged in appropriately formulated

ISSN:0193-7197    

DOI:10.1002/vnl.730100107

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe paper describes the development and properties of a new family of thermoplastic elastomers based on polyvinyl chloride.Comparisons of the new products with traditional flexible PVC's will be presented, pointing up differences in specific gravity, low temperature properties, heat resistance, melt viscosity, and general physical properties such as tensile modulus and elongation.The elastomeric properties of the new materials are explored and compared to some typical cured elastomers—chloroprene, chlorosulphonated polyethylene. The common thermoplastic elastomers based on block copolymers and polyurethanes are also considered in relation to the new compositions. Such properties as compression‐set, flex and fatigue resistance, oil and chemical resistance, weatherability, and performance at elevated temperatures are detailed.The unique feature of this technology that allows one to tailor the surface characteristics from typically high PVC gloss to the fine dull satin finish of cured elastomers is discus

ISSN:0193-7197    

DOI:10.1002/vnl.730100108

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractPolyvinyl chloride is rapidly becoming recognized as a versatile polymer. It has a unique ability to accept additives, and the properties of the finished article often depend more on formulation than the resin itself.A wide variety of chemical may function similary in PVC, yet processors often have to compromise in selecting one additive over another. For example, both tin mercaptides and metal carboxylates function as thermal stabilizers. The mercaptide is superior as a thermal stabilizer while the carboxylate offers better weathering stability. Today's market tends to compromise at the expense of weathering. To compensate, high levels of reflective pigments (TiO2) are used.Recently, we initiated a research program and discovered a class of compounds which provide excellent weatherability with processability comparable to the highly‐efficient tin mercaptide. This cost‐effective development allows reduction of TiO2levels by 25–50%. In addition, dark pigmented profiles remain relatively undeveloped because of serious weathering problems. Accelerated weathering and outdoor exposure tests demonstrate this technology is quite effective for UV stabilization of dark brown sy

ISSN:0193-7197    

DOI:10.1002/vnl.730100109

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractA new class of complex esters offers the capability for tailoring lubrication characteristics to specific PVC applications. The lubricating performance of these esters can be varied from internal to external through changes in carboxylic chain length, polyol moiety, and degree of esterification. Changes in the degree of functionality of the polyol portion of the ester can be used to affect large variations in fusion time and mill stick time. Polyol functionality may also be used to control extrudate gloss without changes in other processing parameters. Dynamic stability is relatively independent of polyol type, with all of the esters providing excellent stability behavior. Carboxylic acid chain length has a pronounced effect on external lubricity, as demonstrated by large changes in mill stick time. Esters based on stearic or longer chain acids provide optimum extrusion processability and yield high gloss extrudates at low extrusion torques. Dynamic thermal stability also increases with acid chain length. The effect of degree of esterifications on lubrication is dependent upon the polyol portion of the ester. In low hydroxyl value esters, the degree of esterification can be used to vary external lubricity.

ISSN:0193-7197    

DOI:10.1002/vnl.730100110

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe strain‐induced crystallization (SIC) behavior of VDC/VC copolymers has a significant effect on processibility on the blown film process. However, data onSICof VCD/VC copolymers has been very limited due to the difficulty of measuring the rapid crystallization rates induced by strain; whereas, crystallization under quiescent conditions has been studied extensively. In this work,SICof VDC/VC copolymers has been calculated from measurements of the adiabatic temperature rise upon stretching of amorphous specimens. The effect of stretching conditions such as strain rate, total strain, and initial temperature and the effect of polymer variables such as copolymer composition, molecular weight, and plasticizer content are determined. It is found that the performance of different VDC/VC copolymers on the film‐blowing process correlates much better with measurements ofSICthan with quiescent crystallization behav

ISSN:0193-7197    

DOI:10.1002/vnl.730100111

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY