Composites of High-Temperature Thermomechanical Pulps and Polylactic Acid

Research output: Contribution to journalArticleScientificpeer-review


Research units

  • Tampere University of Technology


High-temperature thermomechanical pulps (HT-TMP, defibrated at 150 to 170 degrees C) were compared to a reference TMP (defibrated at 130 degrees C) as a reinforcement for polylactic acid (PLA). Composites were prepared by melt compounding, followed by injection molding, gradually increasing the used fiber content from 0 to 20 wt.%. The injection-molded specimens were characterized by tensile and impact strength tests, scanning electron microscopy, water absorption tests, and differential scanning calorimetry. The TMP fiber damage was also characterized before and after melt compounding by optical analysis. At 20% fiber content, the Young's modulus increased significantly, while the tensile strength remained unchanged and the impact strength decreased slightly. All fibers suffered damage during melt compounding, but the tensile strength remained about the same as in pure PLA. All types of TMP were able to increase the PLA rate of crystallization. The HT-TMP fibers were dispersed more evenly in PLA than the 130 degrees C TMP. The 170 degrees C TMP produced composites of lower water absorption than the other two TMP types, probably because of its lower hemicellulose content and its higher surface coverage by lignin.


Original languageEnglish
Pages (from-to)1125-1140
Number of pages16
Issue number1
Publication statusPublished - Feb 2016
MoE publication typeA1 Journal article-refereed

    Research areas

  • Polylactic acid, High-temperature thermomechanical pulp, Hydrophobic fibers, Wood fiber composites, Thermal properties, Mechanical properties, POLYPROPYLENE COMPOSITES, FIBER MORPHOLOGY, CELL-WALL, DEFIBRATION TEMPERATURE, POLYMER COMPOSITES, BARRIER PROPERTIES, WOOD, PLA, CRYSTALLINITY, LENGTH

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