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Heat capacities of polyethylene. IV. High molecular weight linear polyethylene

1976; The National Institute of Standards and Technology; Volume: 80A; Issue: 1 Linguagem: Inglês

10.6028/jres.080a.009

2376-5704

Shu‐Sing Chang,

Advanced Physical and Chemical Molecular Interactions

A high mo le cu lar weight lin ear polyet hyl en e samp le has been studi ed by ad iaba ti c c a lorim e try from 10 to 380 K. Two broad tem pe rature regions of unus ua l spo ntaneo us temperature drift have be e n observed.Th e phenomena occ urrin g around 240 K are simil ar to th a t observe d in other poly• e thyl e ne s amp les st.udi ed in t.hi s se rie s, a nd a re pres um e d to be ca used by t.he re laxa ti onal process e s in the amorphous phase.The weak exo th er mi c be hav ior occ urrin g around 160 K is pres um ed to be ca used by th e s tabi li zation of th e qu e nc hed sa mpl e. Ke y word s : C las s tran s itio n; hea t capacity; hi gh molecu lar weight lin ear polye thyl e ne; polyethylene; temperature drift ; th ermodynam ic properties .1 Co mme rc ial mat erial s a re ide nti fie d in thi s pa per to adequately spec ify the expe rime ntal procedure.Such identifi ca tion does not impl y recomme nd a tion or e nd orse me nt by th e Na li onal Bureau of Standa rd s.