ISSN:0193-7197    

DOI:10.1002/vnl.730100302

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractAssessing the fire hazard of a material has three facets: (a) the generation of heat and combustion products; (b) their transport to the vicinity of the building occupant; and (c) the response of each subject to specific exposures. In this study, interest has focused on the aspect of HCl decay. Two models for HCl generation, transport, and decay have been developed: an empirical and a rigorous model. Both have been applied to predict the behavior of HCl in small and large scale fire experiments. The rigorous model accounts for primary variables (humidity and type and extent of surface) in such a way that it is essentially independent of scale and specific geometry. The results show that the fire hazard of chlorinated materials is exaggerated unless HCl decay is considered.

ISSN:0193-7197    

DOI:10.1002/vnl.730100303

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractAs long as 20 years ago the need was considered to extend codes concerned with flammability and/or flame spread, to include combustion toxicity requirements. Due to the lack of suitable toxicity tests at that time, the added code requirements for combustion toxicity were not enforceable. Vinyl resin manufacturers have been cited as purveyors of hazardous materials which, when burned, generate a noxious toxic hazard due to the fumes they produce in a fire. Overlooked are such factors that commercial vinyl products have inherent low ignition and flame spread rates and only generate potentially toxic gases when quantities of other materials burning around them heat the vinyls to the decomposition point. In 1983 New York State commissioned a study by A. D. Little Inc. to assess the feasability of incorporating combustion toxicity requirements into building material and furnishing codes of New York State. This paper summarizes these findings, including evaluation and analysis of the data generated by the two tests selected as best meeting the seven critical criteria. Due to differnt combustion toxicity rankings provided by the two test methods, controversial and confusing interpretations reign. As a result, the author provides a four step set of recommendations.

ISSN:0193-7197    

DOI:10.1002/vnl.730100304

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractAs a result of reports that vinyl chloride monomer migrated at detectable levels into alcoholic beverages stored in poly(vinyl chloride) bottles, FDA proposed to ban the use of rigid PVC for distilled spirits in 1973. A review is presented of FDA's revised proposal for the regulation of PVC food packaging issued in 1986 and some recent developments that have further delayed FDA's issuance of a rule that would lead to the use of PVC in liquor bottles. Despite significant technological improvements in the manufacture of rigid PVC, which has led to drastic reduction of residual vinyl chloride monomer (RVCM) to safe levels, FDA action on PVC has remained stalled. It is concluded that final action by FDA may well depend not on scientific principles, but on the Agency's ability to effectively reconcile the correct scientific, health and legal solutions with the political pressure being exerted by environmentalist groups.

ISSN:0193-7197    

DOI:10.1002/vnl.730100305

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractDEHP has had widespread use in flexible vinyls, serving as the workhorse plasticizer. Extensive studies have shown that DEHP has a very low order of toxicity. Originally, concern developed over the effect DEHP might have on the environment. In 1980 results of two‐year feeding studies on rats and mice by NCI caused the emphasis to shift to health aspects of DEHP. Although evidence to date shows DEHP has extremely low order of toxicity (acute), is a minimal irritant to skin or eyes, and poses no hazard to the environment, the chemical industry will continue investigations of phthalate plasticizer

ISSN:0193-7197    

DOI:10.1002/vnl.730100306

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractToxicity Characteristic Leaching Procedure (TCLP) is the revised original EPA test method “Extraction Procedure” (EP) designed to eliminate its recognized shortcomings. TCLP, like its predecessor EP, is used to identify those wastes which pose a hazard to human health and the environment if improperly managed. The objective of both procedures is to identify wastes which pose hazards due to their potential to leach significant levels of specific toxic chemicals. The new test is designed to improve the leaching of organic constituents and expands the toxicity characteristic list to include 38 additional chemicals. The expanded criteria list of hazardous constituents includes vinyl chloride monomer. This means if a PVC sample does not pass the TCLP test it becomes a hazardous waste when discarded The regulatory burden and disposal costs then increase significantly, perhaps exponentially, Adoption of TCLP now may require PVC users to obtain Federal or State permits to install facilities to comply with regulatory standards. Indications are that EPA may promulgate the final rule in 1988, but exclude waste wa

ISSN:0193-7197    

DOI:10.1002/vnl.730100307

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractRoetling's adaptation of the Ree‐Eyring model to represent tensile shear banding of polymers in terms of two relaxation processes and Mansfield's model to describe alpha and beta relaxation processes in terms of polymer segment mobility are combined with the particulate structure of poly(vinyl chloride) (PVC) to give a more detailed connection between the macroscopic yielding process and the microscopic mobility of polymer segments. Mansfield's model for relaxation processes is cast in terms of intra‐ and inter‐molecular interactions that serve to hinder orientational motions of polymer segments. The viscoelastic beta process in PVC is interpreted in terms of this model to be a hindered rotation of a segment about its main chain axis. About half of the activation energy of the beta process can be estimated from the barriers hindering rotation in simple alkyl halides. According to tensile yield studies it is the beta process that governs the tensile yield behavior of PVC at high loading rates or low temperatures, i.e. the brittle to ductile transition. Viscoelastic measurements were made on milled compression molded powder blends of PVC of differing K‐values (55–69), over a frequency range of 0.1 to 500 Rad/sec. and a temperature range of −140°C to 20°C. The dependence of the complex compliance on frequency and temperature was represented in terms of a five parameter model proposed by Havriliak and Negami to represent the dielectric dispersions of polymers. The five parameters and their dependence on temperature were estimated using the multi‐response statistical techniques developed by Havriliak and Watts. The parameters are interpreted in terms of Mansfield segmenta

ISSN:0193-7197    

DOI:10.1002/vnl.730100308

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThe versatility of poly(vinyl chloride) is largely a result of its capability to be modified by a wide variety of formulating additives, especially plasticizers and fillers. These additives vary widely with respect to their chemical composition, and the concentrations used in PVC, which impart significant effects on costs and performance properties. Computerized formulating programs have begun to replace laboratory testing directed at developing cost effective PVC formulations. A broad data base is required to capitalize on the many cost effective options posed to the PVC formulator. The Marketing Technical Service function of Exxon Chemical Co. utilizes COPPCO, COmputerized Profit/Performance COnsulting, to evaluate the options. The coherent data base contains 34 different plasticizers ranging from 25 to 90 phr, and can accommodate filler effects over a range of zero to 100 phr. COPPCO performs the following functions: cost and performance properties are predicted for specific formulations; lowest cost formula is defined to satisfy a specified set of performance properties; cost and performance properties are predicted for blends of plasticizers in unfilled and filled PVC compositions; performance properties are graphically presented as a function of PHR of plasticizer and plasticizer blends; graphic contours define constant property values as a function of plasticizer and of filler levels; and three dimensional response surfaces reflect the coincidental variation of both plasticizer and filler levels. COPPCO utilizes SAS (Statistical Analysis System) and Telegraph graphics, combined with sophisticated mainframe programs developed specifically to provide the desired output. Unlimited cost and performance options of the PVC formulator can be evaluated in milliseconds, vs. the traditional laboratory exercises which result in limited data after one to two weeks of sample preparation and testing.

ISSN:0193-7197    

DOI:10.1002/vnl.730100309

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractThis study examines the recyclability of PVC bottles into other PVC products. Post consumer bottles can potentially be granulated and used, without further treatment, in the production of these products. Washing will allow the granulate to recover most of the properties of the original bottle compound, by removing paper labels and residual product contamination. Plastic contaminants, such as those from caps and other plastic bottles, show little effect on several physical properties at levels up to 3%. This granulate can thus be used as a significant portion of the raw material feed for a number of PVC products including DWV (drain/waste/vent) pipe, pipe fittings, rigid sheet, bottles, etc. Post consumer PVC bottle granulate thus constitutes a valuable resource; the recyclability of PVC packaging thus is a question of collection.

ISSN:0193-7197    

DOI:10.1002/vnl.730100310

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY

摘要:

AbstractPVC is the second largest polymer produced and used in the U.S. It is a self‐extinguishing material with excellent chemical resistance and good dimensional stability. It's greatest asset, however, is it's versatility. By specifically formulating PVC with the numerous types of additives available, a balance of properties can be tailored for a wide range of applications. The most serious disadvantage of PVC is it's low heat resistance which limits the service temperature of finished articles to about 70°C. Now an additive is available that can be formulated with PVC to form miscible, transparent blends with increased service temperature. With proper formulating, the higher HDT can be achieved without sacrificing other properties. It is especially important in clear PVC applications where no increase in haze was noted with the addition of the acrylic imide copolymer. Indications are that substantial market opportunities exist for a high heat PVC. Major market segments include clear packaging with it's need for hot‐fill containers, building products where the desire to use darker colors provides the driving force, and in custom injection molding applications where improved heat resistance would allow vinyl to compete more effectively with FR‐sty

ISSN:0193-7197    

DOI:10.1002/vnl.730100311

出版商:Society of Plastics Engineers    

年代:1988

数据来源: WILEY