Elastomers polypropylene oxide

If polypropylene is too hard for the purpose envisaged, then the user should consider, progressively, polyethylene, ethylene-vinyl acetate and plasticised PVC. If more rubberiness is required, then a vulcanising rubber such as natural rubber or SBR or a thermoplastic polyolefin elastomer may be considered. If the material requires to be rubbery and oil and/or heat resistant, vulcanising rubbers such as the polychloroprenes, nitrile rubbers, acrylic rubbers or hydrin rubbers or a thermoplastic elastomer such as a thermoplastic polyester elastomer, thermoplastic polyurethane elastomer or thermoplastic polyamide elastomer may be considered. Where it is important that the elastomer remain rubbery at very low temperatures, then NR, SBR, BR or TPO rubbers may be considered where oil resistance is not a consideration. If, however, oil resistance is important, a polypropylene oxide or hydrin rubber may be preferred. Where a wide temperature service range is paramount, a silicone rubber may be indicated. The selection of rubbery materials has been dealt with by the author elsewhere. ... 

The equilibrium shear modulus of two similar polyurethane elastomers is shown to depend on both the concentration of elastically active chains, vc, and topological interactions between such chains (trapped entanglements). The elastomers were carefully prepared in different ways from the same amounts of toluene-2,4-diisocyanate, a polypropylene oxide) (PPO) triol, a dihydroxy-terminated PPO, and a monohydroxy PPO in small amount. Provided the network junctions do not fluctuate significantly, the modulus of both elastomers can be expressed as c( 1 + ve/vc)RT, the average value of vth>c being 0.61. The quantity vc equals TeG ax/RT, where TeG ax is the contribution of the topological interactions to the modulus. Both vc and Te were calculated from the sol fraction and the initial formulation. Discussed briefly is the dependence of the ultimate tensile properties on extension rate. 

IPDI-based prepolymer. This is an aliphatic prepolymer formed by the reaction of IPDI with polyether polyol (3000 molecular weight PPO-based triol) (PPG = polypropylene oxide). The NCO group content of such systems is about 3.4%, and the viscosity about 15 000 CP at 20°C. Solid content is typically 98%-100%. The general reaction is given in Figure 2.22. This prepolymer may typically be used in two-part elastomer systems. 

Poly(ester-imide) elastomers have been prepared, and contain the reaction product of trimellitic anhydride with polyoxyalkylene diamines like polypropylene oxide diamine. Having excellent tensile strength they are used for making automobile parts [251], or when highly filled they are a suitable replacement for ceramics [252]. 

Polyelectrolytes having bound ions integrated in the polymer backbone are cahed ionenes. Some ionenes have been studied for their bacteriostatic and bactericidal activity. Ionenes with segments of polypropylene oxide in the backbone have been evaluated as thermoplastic elastomers. 

Rubbery behavior—large, reversible extensibility—implies an absence of crystallinity, and this is usually the case for undeformed elastomers. However, small extents of crystallization may be present at ambient temperature in some elastomers, including EPDM with high ethylene content, epichlorohydrin rubber, and polypropylene oxide. The crystallites in these materials can act as reinforcing agents. Many thermoplastic elastomers have crystalline domains that function as reversible crosslinks (Rzymski and Radusch, 2005 Bhowmick and Stephens, 2001). 

Prepolymers of polybutadiene diol (M. 2500), polytetramethylene oxide diol (M. 1400 and M. 2100), and prepolymer of polypropylene oxide diol (M. 1400) were used to obtain segmented elastomers SPU-1 to SPU-5. Prepolymers were prepared by reaction of appropriate diol with 2,4-toluene diisocyanate (2 moles per one mole of diol). Prepolymers of polytetramethylene oxide diol (elastomers SPU-1 and SPU-4) were cured by methylene-bis-o-chloroaniline, MOCA, or by mixture of MOCA and polytetramethylene oxide diol (SPU-2 and SPU-3). SPU-5 samples, prepared from prepolymer of polypropylene oxide diol, were cured by MOCA, and prepolymer of polybutadiene diol was cured by a mixture of MOCA and polytetramethylene oxide diol (SPU-6). Various concentrations of hard segments, Cj, in SPU were set by a ratio of mixture components and molecular weight of prepolymer (Table 10.14). Excess of NCO-groups was in the range 1.03-1.06 for SPU-1 to SPU-5 and 0.99 for SPU-6. All samples were cured at 80°C for 4 days. The... 

Parel Polypropylene oxide elastomers Nippon Zeon Co., Ltd. 

Polypropylene glycol (PPG, polypropylene oxide) n. A family of non-volatile liquids with the general formula HOCH(CH3)-[-CU2CH- CHs)0-]nCH20H. They are similar to the polyethylene glycols, but are more oil-soluble and less water-soluble. They are polyols used in producing polyurethane foams, adhesives, coatings, and elastomers. 

Telechelic macromers have often been used for making block copolymers. Thus the elastomic fibre, spandex (e.g. Lycra), is made from poly-THF, H(0(CH2)4) 0H, with a diisocyanate (to form a urethane), and the thermoplastic elastomer, Hytrel, is composed of blocks of poly-THF and terephthalic esters. Non-ionic surfactants are often block copolymers of polyethylene oxide/polypropylene oxide (prepared by anionic polymerization). 

Polyester soft segments impart better thermal and oxidative stability, oil and solvent resistance, higher abrasion resistance and strength to elastomers, expecially if they crystallize under stress, but they have lower hydrolytic, acid/base and fungus resistance than poly ether urethanes. Polyether urethanes have generally lower Tg and are better suited for low temperatures than the polyester urethanes. Polypropylene oxide-based soft segments are the least expensive, do not crystallize under any conditions and have excellent flexibility. PTMO-based polyurethanes have superior characteristics and an excellent balance of properties. 

PC PE PES PET PF PFA PI PMMA PP PPO PS PSO PTFE PTMT PU PVA PVAC PVC PVDC PVDF PVF TFE SAN SI TP TPX UF UHMWPE UPVC Polycarbonate Polyethylene Polyether sulfone Polyethylene terephthalate Phenol-formaldehyde Polyfluoro alkoxy Polyimide Polymethyl methacrylate Polypropylene Polyphenylene oxide Polystyrene Polysulfone Polytetrafluoroethylene Polytetramethylene terephthalate (thermoplastic polyester) Polyurethane Polyvinyl alcohol Polyvinyl acetate Polyvinyl chloride Polyvinyl idene chloride Polyvinylidene fluoride Polyvinyl fluoride Polytelrafluoroethylene Styrene-acrylonitrile Silicone Thermoplastic Elastomers Polymethylpentene Urea formaldehyde Ultrahigh-molecular-weight polyethylene Unplasticized polyvinyl chloride... 

Ethanox 376 is a stabilizer that provides heat stability by preventing thermo-oxidative degradation during processing and service life. It provides compatibility with resins and extraction resistance. It can be applied in polyolefins, such as polyethylene, polypropylene, polybutene-1 and other polymers such as engineering plastics, styrenes, polyurethanes, saturated and unsaturated elastomers, styrenics, rubber modified styrenics, segmented block copolymers, and PVC. 

Non-discoloring, sulfur containing phenolic antioxidant and stabilizer that provides long-term heat stability by preventing thermo-oxidative degradation. Used for the process stabilization of polyethylene wire and cable resins for polyethylene during extruder compounding. Can also be applied in styrenic polymers, polypropylene, elastomers such as EPDM and SBR and for carboxylated SBR latex, polybutadiene rubber and polyisopropene rubber. 

To further advance the knowledge on swelling of these systems, a study was conducted using elastomers with a limited phase separation. Polyurethanes were made by a two-step process. Polybutadiene diol (M. 2500) polytetramethylene oxide diol (M. 1400 and 2100) were used. Prepolymers were prepared by reaction of one mole of diol and two moles of 2,4-tolnene diisocyanate. Polypropylene glycol triol, Laprol 373 (M. 370) was... 

The flame-retarding of HDPE and PP is not so complex. 4.25 phr. of Saytex BN 451 and 2 phr. of antimony trioxide yield the rating V-2 for polypropylene. 6 per cent of octabromodiphenyl oxide and 3.5 per cent of antimony trioxide in 90.5 per cent of HDPE is rated B2 according to DIN 4102 (cf. Section 3.2.1) while the flammability of a compound with 9 per cent of decabromodiphenyl oxide and 4 per cent of antimony trioxide to 87 per cent of HDPE is rated B1. For reaching the classification V-0, a rather high portion of flame-retardants should be admixed, for example 30 phr of decabromodiphenyl oxide and/or BT 93 is recommended with 10 phr. of antimony trioxide to polypropylene. Masterbatches with these flame-retardants facilitate processing (cf. Table 5.15). The same systems are also used for polyolefin elastomers (such as EPDM) . 

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