Nucleating Agent-assisted Preparation of Polyprolylene (PP)/polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites and Their Characterization
  • Release Date : 28 September 2021
  • Publisher : Unknown
  • Genre : Fibers
  • Pages : 248 pages
  • ISBN 13 : OCLC:438412254
Ratings: 4
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Download or read book entitled Nucleating Agent-assisted Preparation of Polyprolylene (PP)/polyhedral Oligomeric Silsesquioxane (POSS) Nanocomposites and Their Characterization by author: Byoung-Jo Lee which was release on 28 September 2021 and published by Unknown with total page 248 pages . This book available in PDF, EPUB and Kindle Format. "This study investigated the interactions between the molecules of polyhedral oligomeric silsesquioxane (POSS) and sorbitol-type nucleating agents in the development of self-assembled nanoparticles in polypropylene (PP). The nanocomposites thus developed were spun into fibers and the fiber mechanical properties were evaluated as function of POSS chemical structure, POSS content, and nucleating agent content. Two types of POSS were chosen - trisilanolphenyl-POSS (ph-TPOSS) and octaisobutyl-POSS (bu-MPOSS). The former was incompatible with PP but offered strong hydrogen bonding possibility with the nucleating agent. The latter did not interact with the nucleating agent but was compatible with PP. Di(benzylidene)sorbitol (DBS) was used as the nucleating agent, which formed three-dimensional fibrillar networks in PP upon cooling. The hydrogen bonding interactions with DBS improved dispersion of ph-TPOSS in PP and led to formation of POSS nanoparticles with diameter 25-200 nm. It was found that spun fibers of typical PP formulation with 0.3 wt% DBS and 10 wt% ph-TPOSS showed close to 70% reduction in diameter and offered 45 % increase in modulus and 50 % increase in tensile strength compared to unfilled PP. A pressure-driven flow through rectangular shear-cell yielded information on the effect of ph-TPOSS on the development of relative averaged birefringence and the formation of skin-core morphologies. It was found that ph-TPOSS nanoparticles retarded the local relaxation of oriented PP chains. Accordingly, the skin layer thickness increased compared to PP in the presence of 0.3 and 0.5 wt% ph-TPOSS. The crystallization occurred more rapidly when DBS and ph-TPOSS were present. It was found that fibrillar network formation by DBS was hindered in the presence of ph-TPOSS, which was attributed to formation of hydrogen bonding. No such hydrogen bonding occurred in the case of bu-MPOSS and accordingly, DBS fibrillation took place and crystallization occurred without interference by bu-MPOSS molecules. The study also identified that ph-TPOSS molecules can condense if the processing temperature is raised above 210°C."--Abstract.