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Chain scission effect

EPDM rubber Carbonyl absorption Oxidative chain scission Effect of crosslinking [158]... [Pg.865]

Does chain scission effect the mechanical properties of a polymer network in an indirect way, e.g. through the release of stored elastic energy or ensuing radical reactions ... [Pg.175]

Elliot [38] has reported that interfacial adhesion in the NR-PP blend can be enhanced by the addition of small amounts of HOPE. Addition of HDPE does give some improvement in the notched Izod impact strength of NR-PP blend (Fig. 7). The effect of HDPE on the impact modification of NR-PP is associated with the improved crystallinity of PP, enhanced by HDPE. During the mill mixing of NR and PP, chain scission may occur to give polymeric radicals that, on reaction with... [Pg.643]

From the Arrhenius form of Eq. (70) it is intuitively expected that the rate constant for chain scission kc should increase exponentially with the temperature as with any thermal activation process. It is practically impossible to change the experimental temperature without affecting at the same time the medium viscosity. The measured scission rate is necessarily the result of these two combined effects to single out the role of temperature, kc must be corrected for the variation in solvent viscosity according to some known relationship, established either empirically or theoretically. [Pg.152]

The recombination of fragments stemming from one macromolecule, at times shorter than the diffusion time, prevents the linear increase in RD with the absorbed dose per pulse, as not all main-chain scissions result in the formation of fragments. The effect of molecular oxygen on RD in the case of PBS can be interpreted by formation of peroxyl radicals, e.g. [Pg.922]

The effect of oxidative irradiation on mechanical properties on the foams of E-plastomers has been investigated. In this study, stress relaxation and dynamic rheological experiments are used to probe the effects of oxidative irradiation on the stmcture and final properties of these polymeric foams. Experiments conducted on irradiated E-plastomer (octene comonomer) foams of two different densities reveal significantly different behavior. Gamma irradiation of the lighter foam causes stmctural degradation due to chain scission reactions. This is manifested in faster stress-relaxation rates and lower values of elastic modulus and gel fraction in the irradiated samples. The incorporation of O2 into the polymer backbone, verified by IR analysis, conftrms the hypothesis of... [Pg.181]

EB irradiation of polymeric materials leads to superior properties than the 7-ray-induced modification due to the latter having lower achievable dose rate than the former. Because of the lower dose rate, oxygen has an opportunity to diffuse into the polymer and react with the free radicals generated thus causing the greater amount of chain scissions. EB radiation is so rapid that there is insufficient time for any significant amount of oxygen to diffuse into the polymer. Stabilizers (antirads) reduce the dose-rate effect [74]. Their effectiveness depends on the abUity to survive irradiation and then to act as an antioxidant in the absence of radiation. [Pg.863]

The effect of EB-radiation dose intensity on the surface properties of surface and bulk-modified EPDM rubber have been investigated [382]. Predominant chain scission at higher radiation doses... [Pg.885]


See other pages where Chain scission effect is mentioned: [Pg.243]    [Pg.4]    [Pg.100]    [Pg.439]    [Pg.243]    [Pg.4]    [Pg.100]    [Pg.439]    [Pg.436]    [Pg.460]    [Pg.419]    [Pg.443]    [Pg.428]    [Pg.246]    [Pg.270]    [Pg.233]    [Pg.236]    [Pg.96]    [Pg.251]    [Pg.482]    [Pg.30]    [Pg.110]    [Pg.111]    [Pg.332]    [Pg.395]    [Pg.129]    [Pg.135]    [Pg.152]    [Pg.153]    [Pg.167]    [Pg.167]    [Pg.170]    [Pg.171]    [Pg.469]    [Pg.489]    [Pg.490]    [Pg.852]    [Pg.863]    [Pg.870]    [Pg.877]    [Pg.880]    [Pg.892]   
See also in sourсe #XX -- [ Pg.100 ]

See also in sourсe #XX -- [ Pg.439 ]




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Chain effect

Chain scission

Chain scission chains

Effective chain

Radiation chain scission effect

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