Salehiyan, RezaRay, Suprakas SStadler, FJOjijo, Vincent O2019-03-232019-03-232018-12Salehiyan, R. et al. 2018. Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends. Materials, vol. 11(12): doi:10.3390/ma111224501996-1944doi:10.3390/ma11122450https://www.mdpi.com/1996-1944/11/12/2450https://doi.org/10.3390/ma11122450http://hdl.handle.net/10204/10840This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).In this study, small amplitude oscillatory shear tests are applied to investigate the rheological responses of polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends and to correlate their viscoelastic properties with the morphological evolutions during processing. Although the analysis of the elastic moduli reveals some changes as a function of blend composition and processing time, the weighted relaxation spectra are shown to be more useful in detecting changes. The analysis demonstrates that when PVDF, i.e., the more viscous phase, is the matrix, the blend relaxes cooperatively and only a single relaxation peak is observed. By contrast, blends with highly concentrated morphologies do not fully relax, showing instead an upward increasing trend at longer times. This outcome is attributed to the broad distribution of highly concentrated droplets with a high probability of droplet–droplet contacts. Dynamic mechanical analysis (DMA) reveals that crystalline segmental motions attributed to the -relaxation of PVDF at around 100 degrees C are restricted by the highly concentrated morphology of the 50/50 PLA/PVDF blend processed for 10 min. Relaxation analyses of the blends via dynamic oscillatory shear tests and DMA are shown to be powerful tools for investigating small microstructural changes in immiscible polymer blends.enPLA/PVDF blendRheologyProcessing-driven morphologyArticleSalehiyan, R., Ray, S. S., Stadler, F., & Ojijo, V. O. (2018). Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends. http://hdl.handle.net/10204/10840Salehiyan, Reza, Suprakas S Ray, FJ Stadler, and Vincent O Ojijo "Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends." (2018) http://hdl.handle.net/10204/10840Salehiyan R, Ray SS, Stadler F, Ojijo VO. Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends. 2018; http://hdl.handle.net/10204/10840.TY - Article AU - Salehiyan, Reza AU - Ray, Suprakas S AU - Stadler, FJ AU - Ojijo, Vincent O AB - In this study, small amplitude oscillatory shear tests are applied to investigate the rheological responses of polylactide/poly(vinylidene fluoride) (PLA/PVDF) blends and to correlate their viscoelastic properties with the morphological evolutions during processing. Although the analysis of the elastic moduli reveals some changes as a function of blend composition and processing time, the weighted relaxation spectra are shown to be more useful in detecting changes. The analysis demonstrates that when PVDF, i.e., the more viscous phase, is the matrix, the blend relaxes cooperatively and only a single relaxation peak is observed. By contrast, blends with highly concentrated morphologies do not fully relax, showing instead an upward increasing trend at longer times. This outcome is attributed to the broad distribution of highly concentrated droplets with a high probability of droplet–droplet contacts. Dynamic mechanical analysis (DMA) reveals that crystalline segmental motions attributed to the -relaxation of PVDF at around 100 degrees C are restricted by the highly concentrated morphology of the 50/50 PLA/PVDF blend processed for 10 min. Relaxation analyses of the blends via dynamic oscillatory shear tests and DMA are shown to be powerful tools for investigating small microstructural changes in immiscible polymer blends. DA - 2018-12 DB - ResearchSpace DP - CSIR KW - PLA/PVDF blend KW - Rheology KW - Processing-driven morphology LK - https://researchspace.csir.co.za PY - 2018 SM - 1996-1944 T1 - Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends TI - Rheology–microstructure relationships in melt-processed polylactide/poly(vinylidene fluoride) blends UR - http://hdl.handle.net/10204/10840 ER -