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Characteristics of polynorbornene and ethylene‐propylene terpolymer blends
Author(s) -
Wang C. S.
Publication year - 1983
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760230909
Subject(s) - materials science , copolymer , differential scanning calorimetry , glass transition , polymer blend , polymer , composite material , epdm rubber , ethylene propylene rubber , ethylene , ultimate tensile strength , polymer chemistry , natural rubber , thermodynamics , organic chemistry , catalysis , chemistry , physics
In this study characteristics of polynorbornene (PNR) and ethylene‐propylene terpolymer (EPDM) blends were examined in terms of compatibility, cocuring, and ozone resistance. For most of the blend compositions, two glass transition temperatures ( T g ) at about −30 and −50°C were observed from differential scanning calorimetry data for both uncured and cured samples. The transitions correspond to the T g 's of the component polymers, suggesting that the blends are microheterogeneous. The two‐phase blends are difficult to cocure as evidenced by the fact that tensile strengths of the blends, when plotted as a function of blend composition, deviate from the linear or additive behavior. Improved cocuring of the blends, however, can be achieved by matching the cure rates of the components. The ozone resistance of the blends containing 25 percent or more EPDM was substantially improved as compared with that of PNR. Therefore, the newly developed PNR can be used for applications requiring ozone resistance by properly blending it with EPDM.