Studies in the field of polyethylene—V. Correlations between compressibility, crystallinity and molecular weight of high pressure natural polyethylenes

Compressibility of polyethylene under pressure up to 5000 kg/cm2

“…The z obtained by Hellwege (9) was smaller than that of the present work in the whole range of pressure studied, though z at ordinary pressure is identical with that of our experiment. Is6cescu and his coworker calculated z up to 1800 atm for various types of polyethylene (10). The obtained values were slightly larger than those shown in this figure, for example z = 4.3 x 10 .5 atm -~ at 1000 atm at 23 °C.…”

“…The volume change under pressure has also been studied from direct measuring by the use of dilatometry or piezoelectric method (8)(9)(10). In these measurements, however, the obtained data involve informations from amorphous part of polymer as well as from crystalline part.…”

Critical Review of Low-Density Polyethylene’s Partitioning and Diffusion Coefficients for Trace Organic Contaminants and Implications for Its Use As a Passive Sampler

“…Parks and Richards (1949) predicted little change in crystallinity with increasing pressure (around 1% for 100 atm) . This was experimentally confirmed, with minor changes in crystallinity (1–2%, within experimental error) for high molecular weight PE up to 1800 atm . According to Wang et al (2007) the effect of increasing pressure has a rather limited effect on the self-diffusion coefficient of toluene in polystyrene at elevated temperatures .…”

“…58 This was experimentally confirmed, with minor changes in crystallinity (1−2%, within experimental error) for high molecular weight PE up to 1800 atm. 59 According to Wang et al (2007) the effect of increasing pressure has a rather limited effect on the self-diffusion coefficient of toluene in polystyrene at elevated temperatures. 60 Increasing the pressure from 0.1 to 50 MPa (equivalent to 5,000 m depth) reduced the diffusion coefficient by a mere 0.3 log units.…”