Saturated polybutadiene

In the case of hydroxymethyl ated polybutadiene, a greater decrease in the intrinsic viscosity as compared to the saturated polybutadiene was observed (see Table I). This can be attributed to the greater hydrophilic character of the -OH group on the polymer chains. 

Notes The values of A, B, and C and thus of y are based on a reference volume Vre/ = 0.1 nm Polymer notation A d- label preceding the polymer acronym indicates a per-deuterated polymer partially deuterated polymers are labeled as dy, df, etc., for selective deuteration of 3, 4, etc., hydrogens. Numbers in subscripted parentheses after the polymer name indicate the primary comonomer fraction, e.g., SPB(6s) is a saturated polybutadiene with 66 mol% butadiene Polymer acronyms P2VP poly(2-vinyl pyridine), P4MS poly(4-methylstyrene), PBMA poly(n-butyl methacrylate), PCHA poly(cyclohexyl acrylate), PEB poly(ethyl butylene), PIB polyisobutylene, PI polyisoprene, PMMA poly(methyl methacrylate), PPMA poly(n-pentyl methacrylate), PP polypropylene, HHPP head-to-head polypropylene, PS polystyrene, PVME poly(vinyl methyl ether), PXE poly(2,6-dimethyl-l,4-phenylene oxide), SPB saturated polybutadiene, SPI saturated polyisoprene... 

Addition of poly(styrene-block-butadiene) block copolymer to the polystyrene-polybutadiene-styrene ternary system first showed a characteristic decrease in interfacial tension followed by a leveling off. The leveling off is indicative of saturation of the interface by the solubilizing agent. 

The data of Table II indicate that the etch rates for CB and its "homologues"—TP, CO (or TO), and EPM—tend to increase monotonically with a decrease in vinylene (-CH=CH-) unsaturation. The elastomeric EPM was chosen instead of crystalline polyethylene as a model for the fully saturated CB to avoid a morphology factor in etch rates, as was observed with crystalline TB. The difference in etch rates for the partially crystalline TO and the elastomeric CO (ratio of about 1.2 1.0) is attributable more to a morphology difference between these polyoctenamers than to the difference in their cis/trans content. Cis/trans content had likewise no perceptible effect on etch rates in the vinyl-containing polybutadienes (see Table I) if there was a small effect, it was certainly masked by the dominant effect of the vinyl groups. 

The hydrogenation of unsaturated polymers and copolymers in the presence of a catalyst offers a potentially useful method for improving and optimizing the mechanical and chemical resistance properties of diene type polymers and copolymers. Several studies have been published describing results of physical and chemical testing of saturated diene polymers such as polybutadiene and nitrile-butadiene rubber (1-5). These reports indicate that one of the ways to overcome the weaknesses of diene polymers, especially nitrile-butadiene rubber vulcanizate, is by the hydrogenation of carbon-carbon double bonds without the transformation of other functional unsaturation such as nitrile or styrene. 

With respect to the intensity resolution relationship of NSE, PEB-2 [essentially PE with one ethyl branch every 50 main chain bonds the sample is obtained by saturating 1-4 polybutadiene, the residual 1-2 groups (7%) cause the ethyl branches Mw = 73200 g/mol Mw/Mn = 1.02] has two advantages compared to PEP (1) the Rouse rate W/4 of PEB-2 is more than two times faster than that of PEP at a given temperature [W/pEP (500 K) = 3.3 x 1013 A4s 1 W/pEB (509 K) = 7 x 1013A4s-1] (2) at the same time, the topological constraints are stronger. 

In this type of styrenic TPE the polybutadiene mid-block used in the SBS types is replaced with ethylene-butylene which is saturated ... 

The first move in this direction was to improve the weatherability of impact-resistant polystyrene. Because polybutadiene, the most widely used rubber in impact-resistant polystyrene, is unsaturated, it is sensitive to photooxidation, and impact-resistant polystyrene is therefore not suitable for outdoor applications. A saturated rubber might be able to help here. In the ABS sector this has been successfully tried out with acrylate rubber (77) and EPDM (78, 79), and the latter has also been used in impact-resistant polystyrene (80, 81) This development has elicited satisfactory responses only in certain areas and more work still has to be done. For instance, attempts have been made to improve resistance to weathering by using silicone rubber (82 ). This approach is effective, but economic factors still stand in its way. Further impetus may also be expected from stabilizer research. Hindered secondary amines (83), to which considerable attention has recently been paid, are a first step in this direction. 

The product obtained by the partial hydrogenation of polybutadiene (Hydropol) has been used as a wire coating and a saturated ABA copolymer (Kraton) is produced by the hydrogenation of the ABA block copolymer of styrene and butadiene. 

Here PNO2 partial pressure of nitrogen dioxide in pascals (1 Pa = 0.000145 psi), and the activation energy is 3870 kJ/mol. Other saturated polymers are less susceptible to attack by NO2 than most unsaturated polymers such as synthetic rubbers (polyiso-prene, polybutadiene, and butyl rubber). The presence of oxygen also tends to accelerate degradation by NO2. The reaction of sulfur dioxide with saturated polymers is complex, but appears to be activated by ultraviolet radiation. 

These ABA copolymers have an index of refraction of 1.5 and water absorption of about 0.2%. Unless hydrogenated to saturated block copolymers, these unsaturated unstabilized plastics are degraded in sunlight. The polybutadiene domains are attacked by aliphatic hydrocarbon solvents, such as hexane, and the polystyrene domains arc attacked by aromatic hydrocarbon... 

Is)max as shown in the diagrams of Figures 17-19 for the three prepolymer types discussed before (polyester, polyether, and polybutadiene). In the examples shown (Is)m ax is about equal for a poly ether (all polypropylene oxide) and a polyester (ca. 49 parts poly (neopentyl glycol) azelate, 35 parts poly (tripropylene glycol) azelate, 10 parts bis (2-ethyl-hexyl) azelate, 6 parts glycerolmonoricinoleate), and about 2 points higher for a polybutadiene binder (ca. 75 parts polybutadiene and 25 parts of a saturated hydrocarbon as plasticizer). 

It appears from the evolution of the adhesion index that a distinction has to be made between the interactions carbon blacks are able to have with unsaturated or with saturated (or near-to-saturated) elastomers. Thus, the adhesion index of butyl rubber is enhanced upon oxidation of the black, while the reverse is observed with polybutadiene 38). The improvement of the reinforcing ability of carbon black upon oxidation, in the former case, has been interpreted by Gessler 401 as due to chemical interactions of butyl rubber with active functional groups on the solid surface. Gessler, relating the reinforcing characteristics of the oxidized carbon black for butyl rubber to the presence of carboxyl groups on the surface of the filler, postulated a cationic... 

As a result of its saturated polymer backbone, EPDM is more resistant to oxygen, ozone, UV and heat than the low-cost commodity polydiene rubbers, such as natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR). Therefore, the main use of EPD(M) is in outdoor applications, such as automotive sealing systems, window seals and roof sheeting, and in under-the-hood applications, such as coolant hoses. The main drawback of EPDM is its poor resistance to swelling in apolar fluids such as oil, making it inferior to high-performance elastomers, such as fluoro, acrylate and silicone elastomers in that respect. Over the last decade thermoplastic vulcanisates, produced via dynamic vulcanisation of blends of polypropylene (PP) and EPDM, have been commercialised, combining thermoplastic processability with rubber elasticity [8, 9]. 

---