ISSN:0193-7197    

DOI:10.1002/vnl.730110102

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractThe ability of PVC to tolerate large amounts of plasticizers, fillers, and other additives is unique among thermoplastics and has made it possible to develop a wide range of properties in flexible PVC. This versatility, coupled with attractive economics, has been responsible for the growth of flexible PVC over the years. Unfortunately, growth has been slow for many years and flexible PVC markets have been encroached on by competitive materials with higher performance and/or styling advantages. Reasons for the vulnerability of flexible PVC are discussed. In some cases, only minor changes are needed to improve performance while in other cases new developments are needed, many of which are available but not exploited.

ISSN:0193-7197    

DOI:10.1002/vnl.730110103

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractHigh molecular weight plasticizers can be used if they have a lowTgand are miscible with PVC. For example, linear polyesters exhibit miscibility with PVC when their [CH2]/[COO]ratio is intermediate; in that range, as “miscibility window” has been found. However, the degree of miscibility of miscible polymer blends vary with the structure of the polymers involved and thier concentration. The miscibility of these systems is often assessed by the measurement of a singleTgas a function of composition. A careful examination of experimental data of polyester/chlorinated polymer blends, as well as the use of the free volume theory, indicates that several of these systems exhibit a cusp as a function of composition, which is characterized by a critical volume fraction and a critical temperature. Specific examples are gi

ISSN:0193-7197    

DOI:10.1002/vnl.730110104

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractThe Flory‐Huggins interaction parameter,x, has been determined as a function of plasticizer composition, ϕ2, for several ternary mixtures of poly(vinyl chloride) (PVC) and different pairs of plasticizers, selected mainly from the family of aliphatic esters. The method employed was the micro‐determination of the apparent melting temperature of a PVC particle in excess plasticizer. In some systemsXchanged fairly gradually as a function of ϕ2, while other systems exhibited a pronounced minimum in theX– ϕ2plots. Attention has been drawn to the similarity of this latter behavior to the well known co‐solvency effect. The existence of such minima is of partical interest in plasticized PVC fo

ISSN:0193-7197    

DOI:10.1002/vnl.730110105

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractWhen chemical additives were found that could minimize the loss of chemical and physical properties of a thermally‐processable but heat‐sensitive polymer called poly(vinyl chloride) (PVC), an industry was born. And with it grew the world of plastics additives. Stabilizers for PVC became and industry itself, feeding into and off of this versatile polymer industry, in an almost symbiotic relationship. There have been so many types of stabilizers in use throughout the past fifty years: inorganics, leads, organics, barium/cadmiums, calcium/zincs, organotins, and antimony. And so very many more have been conceived but not commercialized: organoleads, organoantimonys, bismuths, indiums, and a myriad of organic chemicals. What are the merits and deficiencies of these stabilizers? What of yesterday's products are still with us? What are the newer types? What might be tomorrow's products? This paper will attempt to review and discuss the past, present, and future of PVC stabilizers; the factors that are responsible for their variety, for influencing their research, development, and commercialization, and how these factors change with t

ISSN:0193-7197    

DOI:10.1002/vnl.730110106

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractThe use of plastic containers will grow 11% per year over the next ten years as metal and glass decline. Plastic is the material of choice for food containers in all areas of food processing including hot‐fill and retort packaging. This is due in large part to the strides that have been made in barrier property improvement, better manufacturing, and improvements in the economics, esthetics, and physical properties of plastics. Hot‐fill and retort packaging account for approximately 64% of the total packaged foods, and in the next 10 years this is expected to increase to 68%. Of the two, the hot‐fill method reportedly will gain in importance while retorting will decline by about 1% per year in effect pushing the growth in hot‐fill packaging to about twice that of the overall food packaging business. Since 1980, PVC bottles have grown from 100 MM lbs to more than 200 MM lbs of resin in 1987 (growth of approximately 15% per year). However, PVC bottles still represent only 7% of all plastic bottles and only 1% of all materials used to make rigid containers—an indication of great future potential. One of the serious disadvantages of PVC, however, is its low heat resistance which limits the service temperature of finished articles to about 70°C. Further penetration by PVC bottles can be accelerated by raising the heat resistance above the hot‐fill levels of 85°C–100°C. This would permit PVC to be used for many food applications such as fruit juices and table syrups. Now an additive is available that can be formulated with PVC to form miscible, transparent blends with increased service temperatures. The miscibility of the glutarimide acrylic copolymers in PVC allows it to significantly improve heat resistance without effecting the optical properties of the container. As a result, single layer PVC bottles can be made on conventional blow molding equipment that can be hot‐filled at 85°C–100°C, have glass‐like clarity, with good impact and moderate oxygen barrier resistance. The discussion will include guidelines for compounding the imide copolymer with PVC, properties attainable, and a look at the economics versus other

ISSN:0193-7197    

DOI:10.1002/vnl.730110107

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractThe UEWS test is described as a sensitive means to measure the stress in a material at which the first inelastic behavior becomes apparent. Particularly interesting observations have been made with PVC, where the aging of the material can be shown in a master curve diagram giving the relation between the UEWS and the age of the material at different molecular weights. Using this test as a tool, the performance of blends can also be measured. Blends of PVCs with different molecular weights and blends with various polystyrenes, polyvinyl acetate, and CPE are discussed.

ISSN:0193-7197    

DOI:10.1002/vnl.730110108

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractDifferential scanning calorimetric (DSC) measurements can be used to infer the degree of fusion of rigid PVC articles. The preferred method involves annealing of the specimen at 260°C for 5 minutes, to erase all crystalline structures, followed by a 2 day storage at room temperature. New crystalline entities that are formed give use to an endotherm in the DSC heating mode. The magnitude of this endotherm divided by the total endotherm observed to 220°C can be used to estimate the degree of fusion of the specimen. Data from various processes and different cross‐sections of extruded pipe are consistent with solvent resistance estimati

ISSN:0193-7197    

DOI:10.1002/vnl.730110109

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

摘要:

AbstractUltra‐high molecular weight PVC resins have properties similar to conventional homopolymer resins, except for a few significant differences. Compounds utilizing these polymers display improved toughness qualities and utility in a wider temperature range. These upgraded properties, combined with the usual advantages of PVC such as colorability, processability, and chemical resistance, should permit these PVC compounds to enter markets previously excluded. New potential markets suggested are footwear utilizing the lighter weight advantage of these tougher compounds, automotive under‐the‐hood applications that employ the broader temperature properties, and replacements for elastomers in gasket and compounds used in automotive and appliance applica

ISSN:0193-7197    

DOI:10.1002/vnl.730110110

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY

ISSN:0193-7197    

DOI:10.1002/vnl.730110111

出版商:Society of Plastics Engineers    

年代:1989

数据来源: WILEY