Thermal, dynamic mechanical, and rheological behavior of linear low-density polyethylene/poly(octadecene-co-maleic anhydride) blends

• Published in: Polymer engineering and science 1988-09, Vol.28 (17), p.1132-1141
• Main Authors: O'Connor, K. M., Orler, E. B.
• Format: Article
• Language: English
• Subjects: Applied sciences; Blends; Exact sciences and technology; Forms of application and semi-finished materials; Polymer industry, paints, wood; Technology of polymers
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.760281708

Blends of linear low‐density polyethylene (LLDPE) and a 50:50 copolymer of octadecene and maleic anhydride (C18‐MAH) were characterized by calorimetry, dynamic mechanical testing, and rheometry. In the solid state, the blends are essentially immiscible. No evidence was obtained for cocrystallization of the LLDPE with the paraf‐finic side‐chains of the C18‐MAH. Interactions between the blend components were observed in three ways. First, presence of the C18‐MAH in the LLDPE melt increases the nucleation rate for LLDPE crystallization. Second, side‐chain crystallization in a portion of the C18‐MAH component equivalent to approximately 15% of the total blend is apparently suppressed in the blends. Third, although the mechanical loss of the blends is essentially a sum of the pure components, the β relaxation of the LLDPE is absent in blends containing more than 20% C18‐MAH. The blends are also immiscible in the melt. The steady and dynamic shear rheology is dominated by the immiscibility and mismatch in viscosity, η, between the two polymers. A linear dependence on blend composition was found for log η in dynamic (small strain) tests. Nonlinear behavior with positive and negative deviations from linearity was found for log η in steady shear (large strain) tests.