Pellethane

Mold shrinkage determined on 0.125 X 3 X 6 in molded plaques actual shrinkage will vary with part size and design. Mold shrinkage values for pellethane ... 

There are five types of thermoplastic rubbers currently available. These are based on (i) Olefinics (e.g. Alcryn, Santoprene) (ii) Polyiuethanes (e.g. Elas-tollan, Caprolan, Pellethane) (iii) Polyesters (e.g. Hytrel, Amitel) (iv) Styrenics (e.g. Solprene, Cariftex) and (v) Polyamides (e.g. Pebax, Dinyl) Some typical properties are given in Table 1.4. 

The materials selected for evaluation included three materials currently being used in these applications Biomer (Thoratec Laboratories Corporation, Emeryville, CA), representative of segmented ether-type polyurethanes Avcothane-51 (Avco Everett Research Laboratory, Inc., Everett, MA), a block copolymer of 10% silicone rubber and 90% polyurethane and Hexsyn (Goodyear Tire and Rubber Company, Akron, OH), a sulfur vulcanized hydrocarbon rubber that is essentially a polyhexene. Also selected, because of their easy availability, were Pellethane (Upjohn Company, North Haven, CT), an ether-type of polyurethane capable of being extruded in sheet form, and a butyl rubber formulation, compounded and molded at the National Bureau of Standards. The material thickness varied, but the sheets were generally about 1 mm thick. 

The majority of the characterization for Hexsyn and Pellethane were conducted at MRC while Biomer was characterized at the University of Washington in St. Louis by Dr. J. Kardos and Avco-thane and butyl were characterized at the National Bureau of Standards by Dr. R. Penn. A few of the characteristics of the... 

Pellethane and Hexsyn are summarized here. The Pellethane 2363-80A tested by MRC is commercially available. Our samples had a tensile strength of 7,830 psi and an elongation of 380% at 37°C. 

Butyl rubber - This material generally had the least endurance in fatigue tests, but it may be adequate for some cardiovascular applications. Advantages include less sensitivity to stress concentrators than Pellethane, a very low permeability to fluids, a moderate creep resistance and widespread availability at low cost. Disadvantages include a relatively low fatigue resistance compared to the elastomers specifically designed for these applications. The rubber tested was not designed for medical applications and had standard rubber additives and modifiers that were cytotoxic unless the material was extracted after manufacture. 

Avalon, Desmopan, Flastollan, Fstane, Irogran, Isoplast, Laricol, Laripur, Pearlcoat, Pearlthane,Pellethane,Texin... 

Texin, Desmopan, Estane, Morthane, Elastollan, and Pellethane. 

There are several other commercial products containing segmented polyurethane (SPU) such as pellethane or cardiothane. These SPUs are widely recognized to possess notable biomedical properties as materials for artificial heart and intra-aortic balloon pumping (IABP), and also as coating materials for pacemaker-lead insulators (See Sect. 4.1). 

Pellethane is an extrudable thermoplastic polyurethane based on MDI and a hydrophobic polyol was used in this application. For the most part, the application was successful, but evidence of stress cracking became apparent. The combination of the hydrolytic environment and the polymer under tension caused failures that led to current leakage and ultimate failure of the device. As a result, softer grades of Pellethane and alternative annealing procedures were adopted and reduced the problem dramatically. 

Despite the improvements, a more durable elastomer was clearly needed. A battery of polyurethane elastomers including Pellethane were prepared and implanted subcutaneously in rats. Before implantation, the polymers were extruded into tubes and elongated over mandrels to 400%. The implants were left in place for 6 months and examined under a scanning electron microscope. One of the better performing polyurethanes was based on poly(l,6-hexyl 1,2-ethyl carbonate) diol. Polyesters typically are considered less durable due to the presence of esterase enzymes in vivo. From the data recovered during the implant period, it was determined... 

Pellethane - [COPOLYMERS] (Vol 7) - [POLYETHERS - TETRAHYDROFURAN AND OXETANE POLYMERS] (Vol 19) - [ELASTOMERS SYNTHETIC - THERMOPLASTIC ELASTOMERS] (Vol 9) - [ELASTOMERS SYNTHETIC - THERMOPLASTIC ELASTOMERS] (Vol 9)... 

Product Estane 58133 Estane 58311 Q-Thane PC86 Texin 480A Pellethane 2102-90A Pellethane 2103-70A... 

Pellethane 2103-80A (Upjohn) poly(co-polytetramethylene ether glycol-diphenylmethane diisocyanate). Polyurethane 2000E poly(co-propyleneglycol-4,4 -diphenylmethanediisocyanate-ethylenediamine). 

All polyurethane materials used in this study were either in the form of extruded tubes (Tygothane, Superthane, Pellethane) or as films cast on clean glass from reagent grade dimethylacetamide (DMAC). Only the luminal surfaces of the tubes and the glassfacing sides of the cast films were observed by ESCA. 

Figure 5. The C-ls spectra for Pellethane after a series of extraction procedures...

Untreated Pellethane Extracted Pellethane Methanol Extract of Pellethane Acetone Extract of Pellethane Polystyrene (MW = 3,000) Polystyrene (MW = 37,000) Polystyrene (MW = 80,000) Polystyrene (MW = 233,000)... 

Pellethane CPR 2102 polyurethane, obtained from the Upjohn Company, was the other polyurethane studied. (Hereafter this material Is referred to as polymer "B .) For polymer B the molar ratio of polyester to MDI Is 2.95, and the ester Is poly(capro-lactone). This material Is reported to have Initial properties similar to polymer A when both materials are post cured at llO C for 16 hours. The polymer B samples were previously post cured. 

B.F. Goodrich) Roylar (Unlroyal) Texln (Mobay) Pellethane (Upjohn)... 

Pellethane . [Dow] Polyurethane elastomers for automotive, health care (tubing, catheter components, trans- rmal patches) applies., in film or sheets as bladdos, liners, or belting in fabricated prods, for casters, athletic... 

Test polymers for visualization studies were polyurethane (Pellethane, 2363-80A, Upjohn), filler-free polydimethylsiloxane (Sil-Med Corporation), two forms of Teflon, sintered (TFE, DuPont) and Fluorofilm (Dilectrix Corporation), and polyurethane-silicone rubber copolymer (AVCOthane 51, AVCO). Samples of 1 cm2 or, for shear studies, 5 X 20 X 0.5-cm sheets, were washed in ionic detergent solution (Alconox) at 60°C for 1 h, rinsed in deionized water, and refluxed in absolute ethanol for 1 h. Materials were dried and stored in a desiccator until use. 

Figure 11. Enhancement of defatted albumin adsorption on Pellethane 2363-80A by binding to octadecyl residues. Symbols represent different derivatization runs.

Materials evaluated in the 20-week in vitro study included Pellethane 2300 Series polyurethane (Upjohn, Inc.), polyphosphazenes PNF-200 and 200M (Firestone Co.), polyHexene-H (Goodrich, Inc.), and Biomer (Ethicon, Inc.). Biomer film was cast from a 10% solution in N,AU-dimethylacetamide (Aldrich) on a glass plate at 60°C. Samples were cut into Vi in. X 6 in. strips, with thicknesses measuring approximately 0.6 mm. Prior to exposure, samples were cleansed with a 1% Triton X-100 (Polysciences, Inc.) solution and rinsed with distilled water. They were then vacuum dried for 25 h, and weighed before exposure commenced. 

Figure 1. Elastomer weight gains due to in vitro lipid sorption. Key , Pellethane Experimental Q> Pellethane 2300 series H, PolyHexene-H O, Biomer A, Polyphosphazene PNF 200 and A, Polyphosphazene PNF 200.

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