ISSN:1083-5601    

DOI:10.1002/vnl.730010302.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

ISSN:1083-5601    

DOI:10.1002/vnl.730010303.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractA computer model is proposed to simulate the flow of molten polymer in the melt conveying zone of extruders provided with mixing pins. This model is based on the calculation of down‐channel velocities within cross sections perpendicular to the flow. A Lagrangian reference frame (i.e. that of the barrel sliding on top of the channel) is used to describe the flow in a convenient manner, the mixing pins being represented as a set of virtual boundary conditions (geometric constraints). The proposed method is compared to a full 3D finite element flow simulation with Newtonian and non‐Newtonian fluids showing a good agreement in term of the pressure drop calculation. Numerical tests are also carried out in the case of a rigid PVC compound used for window profile extrusion. The adequacy found between the predictions and experimental measurements obtained on an industrial extruder confirms the performance of the proposed mo

ISSN:1083-5601    

DOI:10.1002/vnl.730010304.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractPVC pipes are generally stabilized with lead, tin, or calcium‐zinc based additives. The performance of PVC products in outdoor applications is highly dependent on the types of stabilizers used and environmental factors such as UV radiation, temperature, humidity, rain, dust, etc. This study involves two‐year exposure of a lead‐stabilized and titanium dioxide‐pigmented PVC pipe at Dhahran (Saudi Arabia) and Miami, Florida. The white pigmented PVC pipes are mostly used outdoor for low pressure potable water services, irrigation in greenhouses, and electrical conduits in Saudi Arabia. The PVC pipe formulation stabilized with Pb‐stabilizer provides good light stability and is also widely used for potable water pipes. The pipes are exposed not only to the natural environment during outdoor usage but also to high UV doses, and to high temperatures during transportation, installation, and long‐term storage. Changes in the exposed pipe were monitored using Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetery (DSC), and mechanical properties testing. The data show that the PVC pipe lost 50 percent of its elongation at break within 12 to 16 months at Dhahran and more than 24 months in Florida during outdoor exposure. The growth of carbonyl groups and the lowering of the glass transition temperature (Tg) was also observed during this exposure period. The extents of degradation of the PVC pipe exposed at the Dhahran and Florida sites we

ISSN:1083-5601    

DOI:10.1002/vnl.730010305.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractEpoxidized natural rubber is a recently commercialized modified form of natural rubber. This paper is part of our continuing effort to study the responses of this new material to melt mixing and other shaping processes. The Shimadzu capillary rheometer was used to evaluate the composition dependence of miscibility of polyvinyl chloride/epoxidized natural rubber blends (PVC/ENR blends). The rheometer was also used to evaluate the effect of compounding parameters on the rheological properties of the blends. The results confirmed PVC/ENR blends as miscible systems that show a synergism in apparent shear viscosity highlighted by the positive deviation from the logarithmic additivity rule. These results based on capillary rheometry are also in very good agreement with our earlier attempt to predict optimum mixing from torque rheometry by using the Brabender Plastogram as an indicator.

ISSN:1083-5601    

DOI:10.1002/vnl.730010306.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractRigid vinyl foam can currently be found in applications such as profile, sheet, and foam core pipe, but it is still a curiosity in house siding and other wood replacement applications. This paper looks at the potential for vinyl foam as an alternative for wood, comparing its end‐use capabilities. In addition, the various types of extrusion processes, and formulations, are compared, and the effect of certain types of formulation ingredients on density, surface quality, and other physical properties are describe

ISSN:1083-5601    

DOI:10.1002/vnl.730010307.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractIndoor air quality (IAQ) has developed into an important environmental and health concern. IAQ legislation has been introduced in the U.S. Congress. Volatile organic compounds (VOCs) comprise a part of the total concern about IAQ. Types and sources of pollutants contributing to IAQ are identified. Some strategies for reducing VOCs in indoor air are provided, and various sources of VOCs are identified. Various means of reducing VOC emissions from products are presented. Government regulatory agencies have begun to introduce legislation focusing on regulation of IAQ. Discussed is how these regulations, some proposed legislation, and customer concerns will affect both product manufacturers and their suppliers.

ISSN:1083-5601    

DOI:10.1002/vnl.730010308.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper reviews three flexible PVC formulations using various types of alumina trihydrate (ATH) and magnesium hydroxide [Mg(OH)2]. Smoke values are compared. In two of the formulations, Mg(OH)2has better smoke values than ATH; in a third formulation, ATH has better smoke values than Mg(OH)2. However, the third formulation uses an ATH with a very high surface area, which may indicate that smoke suppression may be a function of not only the type of flame retardants used but also surface area.

ISSN:1083-5601    

DOI:10.1002/vnl.730010309.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractThis paper reports on the evaluation of a natural product, candelilla wax, as a possible lubricant for unplasticized PVC formulations stabilized with lead or barium/cadmium chemicals. The lubricant effect of two types of wax (commercial grade and purified by solvent extraction) was evaluated by torque and extrusion rheometry and by differential scanning calorimetry. Commercial lubricants (Loxiol) were used for comparison. The results show that candelilla wax may be used as a lubricant (mainly of the external type) for unplasticized PVC; however, care must be taken when designing formulations to avoid over‐lubrication, specially when lead‐based thermal stabilizers are u

ISSN:1083-5601    

DOI:10.1002/vnl.730010310.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY

摘要:

AbstractNormally one seeks Underwriters Laboratories (UL) approval for one or two specific products. This paper describes how approvals were obtained for a very wide range of filled polypropylenes. Coverage included: talc or calcium carbonate fillers, all filler contents from 10% to 50%, carrier resins from homopolymer to high impact copolymer, minimum thickness down to 1.47 mm (0.058 inch), all colors, and a choice of a single product or a blend of filled and unfilled resin. This gives the customer the widest choice of UL‐approved filled polypropylene

ISSN:1083-5601    

DOI:10.1002/vnl.730010311.n

出版商:Society of Plastics Engineers    

年代:1995

数据来源: WILEY