{
  "abstract": "This study clarifies the mechanical recovery and structural retention of damaged glass fiber-reinforced polypropylene (PP/GF) composites subjected to repetitive sub-melting thermal annealing at 160 °C. Initial thermal annealing increased matrix crystallinity from 0.30 to 0.37 (+23.3%), thereby elevating flexural strength from 103 MPa to 122 MPa (+18.4%). Following one repair cycle, flexural strength was completely restored to 103–105 MPa (100% recovery rate). However, after three repair cycles, short-duration annealing (120 s) resulted in severe mechanical degradation down to 30 MPa (−70.9%), whereas long-duration annealing (1800 s) retained a strength of 59 MPa (−42.7%, preserving 57.3% of initial strength). Concurrently, the crystallinity index increased to 0.49 (+63.3%) for 1800 s. These results establish that extended dwell time at sub-melting temperatures is essential for promoting molecular chain re-entanglement while suppressing void growth. These findings present an engineering guideline for low-energy, structure-preserving repair of thermoplastic composites.",
  "abstract_shown": true,
  "affiliations": [
    "Graduate School of Organic Materials Science, Yamagata University, Yamagata 992-8510, Japan",
    "Department of Polymeric and Organic Materials Engineering, Yamagata University, Yamagata 992-8510, Japan"
  ],
  "article_type": "research article",
  "arxiv": null,
  "author_total": 2,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Tetsuo Takayama",
      "orcid": "0000-0002-5170-8346"
    },
    {
      "affs": [
        1
      ],
      "name": "Jun Funabashi"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9hex212tq8b3c.bib",
  "cited_by": 0,
  "doi": "10.3390/polym18192441",
  "fulltext_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13667669/?tool=EBI",
  "id": "9hex212tq8b3c",
  "issns": [
    "2073-4360"
  ],
  "landing_url": "https://europepmc.org/article/PMC/PMC13667669",
  "language": "eng",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "2507|Polymer crystallization and properties"
    ]
  ],
  "openalex": "W7220837323",
  "pdf_url": "https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13667669/pdf/?tool=EBI",
  "pmcid": "PMC13667669",
  "pmid": null,
  "published": "2026-10-01",
  "publisher": "MDPI AG",
  "ris": "https://research.draconitic.com/paper/9hex212tq8b3c.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:35Z",
      "native_id": "PMC:PMC13667669",
      "source": "europepmc",
      "url": "https://europepmc.org/article/PMC/PMC13667669"
    },
    {
      "first_seen": "2026-10-30T12:18:44Z",
      "native_id": "10.3390/polym18192441",
      "source": "crossref",
      "url": "https://www.mdpi.com/2073-4360/18/19/2441"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:2507|Polymer crystallization and properties",
      "subfield": "materials-polymers"
    }
  ],
  "title": "Mechanical Recovery of Damaged Glass Fiber Reinforced Polypropylene via Repetitive Sub-Melting Thermal Annealing: A Molecular and Structural Study",
  "title_text": "Mechanical Recovery of Damaged Glass Fiber Reinforced Polypropylene via Repetitive Sub-Melting Thermal Annealing: A Molecular and Structural Study",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:18:44Z",
  "url": "https://research.draconitic.com/paper/9hex212tq8b3c",
  "venue": "Polymers",
  "versions": []
}