HD-Polyethylene

HD. Polyethylene is suitab e for a number of applications at 100°C for limited periods, depending on the environment. o ... 

The Course of Thermooxidative Degradation of LD- and HD- Polyethylene under Accelerated Testing Conditions... 

The results presented here illustrate the general feasibility of this technique. They relate primarily to the behavior of thermal and current noise in the glass transition (Tg) or melting (Tm) region of an amorphous (polystyrene) and a crystalline (HD-polyethylene (HDPE)) polymer rendered conductive by the addition of minor amounts of carbon black, and further they relate to the noise of aqueous solutions of certain polymers during Couette flow. Because of experimental diflBculties, noise measurements on solid polymers during deformation and flow have not yet produced useful results. 

Fig. 6 A log-log plot of the rate of crosslinking measured as gel content versus li t intensity for HD polyethylene.

Describe the differences in molecular structure, methods of polymerization and general properties between low-density (LD) and high-density (HD) polyethylene. 

Fig. 3-25 Thermogravimetry of HD-Polyethylene (TG 750) Heating Rate P 10 K/min Gas Flow Rate 25 cmVmin...

The HD polyethylenes which may be regarded as long chain n-aUcanes exhibit the same behavior. Their peak temperatures under analogous experimental conditions (at 7 bar) are somewhat higher, however the scattering is very small and independent of molecular weight ... 

The pyrolysis of HD polyethylenes, which do not evaporate due their molecular size, gives values for the arithmetical means of E and log A which are of the same magnitude as... 

Table 3-14 DSC Pyrolysis of n-AUcanes and HD-Polyethylenes Statistical Evaluation...

Table 3-17 Oxidation Kinetics according to ASTM E 698-79 of n-Alkanes, HD-Polyethylenes, Naphthenes, and Olefins Atmosphere Air Pressure 7 bar...

Bredun [342] investigated the adhesion of soil to a steel plowshare as well as to the same plowshare coated with films of Kapron [polycaprolactam], polyamide P-68, a fluoroplastic, HD polyethylene, polyvinyl butyral, and a polymethyl acrylate. The lowest value of soil adhesion was found for the fluoroplastic, and the greatest wear resistance for the polymethyl acrylate. 

Obtain DSC thermal curves of several semicrystalline polymers such as polymethylmethacrylate (PMMA), polystyrene, polycarbonate, high-density (HD) polyethylene, and low-density (LD) polyethylene, and look for the glass transition in these polymers. The DSC run may need to be repeated twice with rapid cooling between runs. Many as received polymers will show a small peak on top of the glass transition on the first run due to relaxation effects in the polymer. The second run should not show this peak, but only a step change in the baseline. Compare your values of to literature values. Deviations may indicate the presence of plasticizers or other additives in the polymer. 

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