Influences of PP-g-MA on the surface free energy, morphologies and mechanical properties of thermoplastic polyurethane / polypropylene blends

• Published in: Journal of polymer research 2015-08, Vol.22 (8), p.1-10, Article 159
• Main Authors: Jia, Shikui, Zhu, Yan, Wang, Zhong, Chen, Ligui, Fu, Lei
• Format: Article
• Language: English
• Subjects: Blends; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Free energy; Industrial Chemistry/Chemical Engineering; Mechanical properties; Morphology; Original Paper; Polymer blends; Polymer Sciences; Polypropylenes; Scanning electron microscopy; Urethane thermoplastic elastomers
• ISSN: 1022-9760; 1572-8935
• DOI: 10.1007/s10965-015-0800-9

The effects of polypropylene-g-maleic anhydride (PP-g-MA) addition on the surface free energy (SFE), morphologies, and mechanical properties of thermoplastic polyurethane (TPU)/polypropylene (PP) blends were investigated in this study. Specifically, the SFEs of the unmodified and PP-g-MA-modified TPU/PP blends were studied through contact angle (CA) measurements; when PP-g-MA content was increased from 3 to 11 phr, the SFE of the blends decreased with different TPU/PP blending ratios while the corresponding CA increased. This decrease was attributed to the interaction between PP-g-MA and TPU. Wide-angle X-ray (WAXD) diffraction results indicated that the crystalline morphology of the blends was not significantly influenced by PP-g-MA. This morphology was observed through scanning electron microscopy (SEM), and the results showed that the TPU/PP blends exhibited an incompatible microstructure that improved with the addition of PP-g-MA. The partial disperse size curve indicated the changes in partial disperse phase size as observed through SEM. Moreover, the fine and mean partial dispersion of the TPU/PP blend was initiated by increasing PP-g-MA content. Specifically, the mechanical properties of the TPU/PP blend were optimized with the addition of 7 phr PP-g-MA. The thermogravimetric (TG) curves suggested that the addition of PP-g-MA could enhance the miscibility of TPU/PP blends.