ISSN:0193-7197    

DOI:10.1002/vnl.730160402

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

ISSN:0193-7197    

DOI:10.1002/vnl.730160403

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThere exist important industrial applications, such as hoses or plastic windows, dealing with closely combining plasticized and rigid poly(vinyl chloride). Nevertheless, migration of plasticizer causes severe variation of the mechanical performance of the end‐products. This work comprises an effort to investigate and understand these phenomena, also as an extension of previous work of ours in migration to liquid environments. The common system plasticized PVC/dioctylphthalate/unplasticized PVC was studied under two‐sided diffusion conditions, i.e., from a thin sheet of plasticized sheet. The whole assembly was placed between two glass plates and then was held in an oven at 64°C to simulate accelerated test conditions. Some pressure was also applied to ensure perfect contact between the plastic sheets. Three different levels of initial plasticizer concentration (48, 66, and 100 phr) have been considered for a period of about five months, until equilibrium was reached. During this period the migration process was monitored by weight changes. Plots ofMt/M∞vs.t½, whereM∞the amount migrated at equilibrium andMtthe amount lost at timet, resulted in evident linear relationship. Therefore, it was proved that the Fick's law approximation for short times can be used to describe the migration kinetics for this solid/solid system. On the other hand, macroscopic observations revealed that no plasticizer was accumulated at the interface, i.e. all plasticizer leaving the plasticized sheet entered the rigid ones. Finally, it seems that the controlling stage is the diffusion inside plasticized PVC while possible annealing of the plasticized polymer structure cannot be

ISSN:0193-7197    

DOI:10.1002/vnl.730160404

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThe ability of different organic additives to increase the bulk density (BD) and the free flow (FF) of PVC was investigated. PVC was treated by quarternary ammonium salts, low‐molecular glycols, polyethylene glycols, polyethylene wax, stearic acid, butyl stearate, oxyethylated fatty acids and alcohol, non‐oxyethylated and oxyethylated partial fatty acid esters of polyhydric alcohols. Increasing one of the mentioned values is not always accompanied by increasing the other. There exist additives which increase the BD only, the FF only, and both values simulataneously. The BD of treated PVC is often instable; it may increase and decrease on standing. The additives used do not affect the structure of PVC particles, but may change the volume of external voids between them. The efficiency of each additive depends on its polarity and structure of the chains. The mechanism of the action of additives altering the BD and FF was considered. It was expected that the additives leading to denser packing of the PVC powder reduce the interparticle interaction at the expense of particle‐additive intera

ISSN:0193-7197    

DOI:10.1002/vnl.730160405

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThe effect of blending various thermoplastics and elastomers with melt processable rubber was studied using ECHIP experimental design. This study shows that with a minimum of tests, key property effects, interrelationships, synergisms, etc., can be identified. The data is useful in guiding the user to produce blends that will optimize properties within a given cost restraint.

ISSN:0193-7197    

DOI:10.1002/vnl.730160406

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractThe performance standards for flexible PVC compounds continue to become more demanding as manufacturers pursue more value‐added applications traditionally dominated by rubbers and thermoplastic elastomers. Blending of PVC with other polymers has proven to be a viable approach in developing higher performance flexible PVC‐based materials. This paper will review some of the typical approaches to producing PVC‐based elastomers, and show how these standard flexible PVC blends compare to a newly developed family of PVC alloys. The advantages of these materials will be discussed, and some examples of commercial materials and their application will also be rev

ISSN:0193-7197    

DOI:10.1002/vnl.730160407

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractOne of the problems faced by plastics design engineers, in addition to anyone involved in resin selection in new product development, is access to comparable data among similar products from different material suppliers. This stems from the lack of standardization in the acquisition and reporting format for materials properties data in the plastics industry. Currently, a multiplicity of national test standards is widely used in the acquisition of the data, which often allows a broad flexibility in the choice of test specimen shapes and geometry, conditions for preparing the test specimens, test variables, and test conditions, in addition to units, rendering any comparison between materials extremely difficult. ISO 10350 and 11403, Parts 1, 2, and 3, were developed specifically to address these issues for the acquisition of the data, and the CAMPUS database was developed as a tool for standardization of the reporting format for plastics properties. The real driving force for standardization at the international level is the growing need for comparable data on a global basis because of the emerging global nature of the manufacturing industry and the cost savings. This paper will discuss the rationale, driving forces, and the status of the worldwide standardization efforts, along with the benefits and experience gained to date.

ISSN:0193-7197    

DOI:10.1002/vnl.730160408

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractMiscibility in poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends was studied by examining evidence from tensile, impact, and physical properties. The observation of synergism in tensile strength, percent elongation at break, hardness, and relative density has reaffirmed PVC/ENR blends as miscible systems. Studies of impact properties, however, revealed that the blends are microheterogeneous in nature. This could be attributed to the large sizes of polymer molecules involved and the microgel content of ENR‐50. Results from Fourier transform infrared spectroscopy (FTIR) revealed that hydrogen bonding is extensively involved in PVC/ENR systems. This evidence unveiled the exact nature of the specific interactions responsible for miscibility and hence the enhanced mechanical properties of PVC/ENR blend

ISSN:0193-7197    

DOI:10.1002/vnl.730160409

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractMiscibility in poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends was further investigated by means of dynamic mechanical analysis. The single glass transition temperature shown by the blends supported earlier observations of miscibility Furthermore, observed synergism in storage modulus has again reaffirmed the miscibility of these blends. A critical examination of the damping peaks at various compositions again revealed the microheterogeneous nature of the blends. Some theories relating glass transition temperature and modulus with miscibility were also used to examine miscibility. Agreement of the results with theories proposed by Gordon—Taylor and Kleiner has provided a further insight into the miscible nature of PVC/ENR blend

ISSN:0193-7197    

DOI:10.1002/vnl.730160410

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY

摘要:

AbstractSurface defects in injection molded PVC parts have long been analytically unpredictable. These defects are typically caused by thermal instability and flow instability of the material. There exists a need to analytically predict these defects through the use of mold filling simulation. This paper documents an experimental approach to predicting surface defects on injection molded PVC parts through the use of material characterization, mold filling simulation correlation, and verification tests.

ISSN:0193-7197    

DOI:10.1002/vnl.730160411

出版商:Society of Plastics Engineers    

年代:1994

数据来源: WILEY