Sheet Extrusion and Thermoforming

Polycarbonate is an extremely versatile polymer with a wide range of applications. Its stifhiess, high heat distortion temperature, impact resistance, and clarity make it a favorite choice for durable goods wth demanding application requirements. Its high modulus allows it to be used in many automotive, medical and domestic applications. 

How does the molecular architecture of the bisphenol molecule affect the physical properties of the final polycarbonate polymer  

Why is it necessary to cap off the polycarbonate chains with a monofunctional molecule when producing the polymer via interfacial polymerization  

What advantages does melt esterification have over interfacial polymerization in manufacturing polycarbonates  

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Sheet Extrusion and Thermoforming. Sheet for thermoforming and analogous operations is usually formed by extmding the melt through a slot die onto a set of poHshed chill roUs. The sheet is usually approximately 150 cm wide. After rapid cooling, the web is coiled or cut into sheets. Polystyrene, PVC, polyethylene, polypropylene, and filled polypropylene are prepared in sheet form by extmsion. 

Fortiflex . [Solvay Polymers] HDPE resins for inj. and btow molding of automotive, cosmetic, household and industrial goods, sheet extrusion and thermoforming, pipes, films. 

Since PVC is known to be quite miscible with PMMA (miscibility with an LCST behavior) [Jager et al., 1983] and is also low in cost, some blends of PVC and PMMA have been used in sheet extrusion and thermoforming applications. However, the acrylic PVC compositions commercially used are invariably contain an acrylic coreshell rubber (PMMA-g-n-BuA or MBS type) to get high toughness), with some PMMA, to reduce the cost/impact performance balance. The role of PVC in these blends is to reduce cost and impart some degree of flame-retardancy. The acrylics definitely help in the processability of PVC. These blends have already been discussed under PVC heading. 

Since PVC is known to be quite miscible with PMMA (miscibility with an LCST behavior) (Jager et al. 1983) and is also low in cost, some blends of PVC and PMMA have been used in sheet extrusion and thermoforming applications. 

Clear extrusion sheet grades are designed for extrusion and thermoforming applications, and like other NatureWorks PLA polymers, use conventional processing techniques and equipment. Potential uses include dairy containers, food service ware, transparent food containers, blister packs, and cold drink cups. 

Chem. Descrip. HOPE with antioxidants CAS 9002-88-4 EINECS/ELINCS 200-815-3 Uses Pipe coating resin for corrosion resist, coating on buried metal pipes, profile extrusions, and sheet extrusions for thermoforming for fo(xl contact... 

PLA have been used in films for packaging, thermoformed and injection moulded disposable rigid containers (for example, food containers and trays), blown flasks and bottles, filaments, and biomedical uses (capsules for drug delivery, fibers for tissues and absorbable/degradable surgical sutures, and internal bone fixation implants). It is a polymer with consolidated use in the medical area, due to its biocompatibility and biodegradability in the human body. PLA-based resins may be modified to adapt to many applications, from disposable food-service items to sheet extrusion, and coating for paper [40]. 

Polyallomer is used for blow-molded bottles, wire coating, film, sheet and pipe extrusion, and thermoforming applications. Applications also include automotive... 

The extrusion process is versatile enough to be adapted to a make wide range of products. One example is blow molding to produce hollow plastic articles such as bottles. This is a combination of extrusion and thermoforming. A hollow tube called a parison is extruded from an annular die. The parison is inflated in the heated softened state inside a mold until the parison conforms to the shape of the mold. The mold is then opened and the bottle released. Another extension of extrasion is the extrusion coating in which a metal wire, paper or a metallic sheet is coated with plastic film extruded from a suitably designed die. 

Drickman, R. and McHugh, K.E. (1993) Balancing extrusion and thermoforming capability for polypropylene.. Plast. Film Sheeting, 9, 22-34. 

The main stream of wood fiber PP composites is short fiber reinforced, suitable for typical thermoplastic processing. The main steps of this technology are (1) pre-mixing, (2) plastic transformation of the melt (typically sheet extrusion), and (3) thermoforming (vacuum- or pressureforming) of the sheet. 

UDEL Polysulfone can be fabricated by the melt processing techniques available for thermoplastics, injection molding, extrusion and thermoforming. For injection molding, melt temperatures of 650-750°F, mold temperatures of 200-300 F and injection pressures of 15,000-20,000 psi have proved suitable. For extrusion, melt temperatures of 600-700 F are required. For sheet extrusion, the take-off rolls must be capable of being controlled between... 

Thermoforming and Extrusion. Improved equipment and polymers have increased the capabiUty to extmde and thermoform polypropylene however, consumption of polypropylene in these areas has not grown dramatically. Drinking straws are commonly extmded from polypropylene, however most larger diameter tubes, such as pipes and conduits, are predominantly extmded from other thermoplastics. Extmded sheet is thermoformed into food containers and trays polypropylene is used when microwavabiUty is desired. 

PBT-PC blends show increased melt strength allowing them to be easily processed by blow molding and profile extrusion. The PBT-PC blends have been extruded into sheet and thermoformed into parts. Enhanced melt strength allows PBT-PC blends to be foamed. Structural foam grades for injection molding (10-30% density reduction) are commercially available. 

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