{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,11]],"date-time":"2026-07-11T11:09:30Z","timestamp":1783768170968,"version":"3.55.0"},"reference-count":55,"publisher":"MDPI AG","issue":"16","license":[{"start":{"date-parts":[[2021,8,23]],"date-time":"2021-08-23T00:00:00Z","timestamp":1629676800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005280","name":"Technick\u00e1 Univerzita v Liberci","doi-asserted-by":"publisher","award":["SGS-2019-5015"],"award-info":[{"award-number":["SGS-2019-5015"]}],"id":[{"id":"10.13039\/501100005280","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Ministry of Education, Youth and Sports of the Czech Republic and the European Union \u2013 European Structural and Investment Funds in the frames of Operational Program Research, Development and Education","award":["CZ.02.1.01\/0.0\/0.0\/16_019\/0000843"],"award-info":[{"award-number":["CZ.02.1.01\/0.0\/0.0\/16_019\/0000843"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>The proper choice of a material system for bioresorbable synthetic bone graft substitutes imposes strict requirements for mechanical properties, bioactivity, biocompatibility, and osteoconductivity. This study aims to characterize the effect of in-mold annealing on the properties of nanocomposite systems based on asymmetric poly(l-lactide) (PLLA)\/Poly(d-lactide) (PDLA) blends at 5 wt.% PDLA loading, which was incorporated with nano-hydroxyapatite (HA) at various concentrations (1, 5, 10, 15 wt.%). Samples were melt-blended and injection molded into \u201ccold\u201d mold (50 \u00b0C) and hot mold (100 \u00b0C). The results showed that the tensile modulus, crystallinity, and thermal-resistance were enhanced with increasing content of HA and blending with 5 wt.% of PDLA. In-mold annealing further improved the properties mentioned above by achieving a higher degree of crystallinity. In-mold annealed PLLA\/5PDLA\/15HA samples showed an increase of crystallinity by ~59%, tensile modulus by ~28%, and VST by ~44% when compared to neat hot molded PLLA. On the other hand, the % elongation values at break as well as tensile strength of the PLLA and asymmetric nanocomposites were lowered with increasing HA content and in-mold annealing. Moreover, in-mold annealing of asymmetric blends and related nanocomposites caused the embrittlement of material systems. Impact toughness, when compared to neat cold molded PLLA, was improved by ~44% with in-mold annealing of PLLA\/1HA. Furthermore, fracture morphology revealed fine dispersion and distribution of HA at 1 wt.% concentration. On the other hand, HA at a high concentration of 15 wt.% show agglomerates that worked as stress concentrators during impact loading.<\/jats:p>","DOI":"10.3390\/polym13162835","type":"journal-article","created":{"date-parts":[[2021,8,23]],"date-time":"2021-08-23T23:19:33Z","timestamp":1629760773000},"page":"2835","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Effect of In-Mold Annealing on the Properties of Asymmetric Poly(l-lactide)\/Poly(d-lactide) Blends Incorporated with Nanohydroxyapatite"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-6686-6462","authenticated-orcid":false,"given":"Martin","family":"Boruvka","sequence":"first","affiliation":[{"name":"Department of Engineering Technology, Faculty of Mechanical Engineering, Technical University of Liberec, Studenstka 2, 461 17 Liberec, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cenek","family":"Cermak","sequence":"additional","affiliation":[{"name":"Department of Engineering Technology, Faculty of Mechanical Engineering, Technical University of Liberec, Studenstka 2, 461 17 Liberec, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8749-3586","authenticated-orcid":false,"given":"Lubos","family":"Behalek","sequence":"additional","affiliation":[{"name":"Department of Engineering Technology, Faculty of Mechanical Engineering, Technical University of Liberec, Studenstka 2, 461 17 Liberec, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1160-9885","authenticated-orcid":false,"given":"Pavel","family":"Brdlik","sequence":"additional","affiliation":[{"name":"Department of Engineering Technology, Faculty of Mechanical Engineering, Technical University of Liberec, Studenstka 2, 461 17 Liberec, Czech Republic"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,8,23]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"Nagalakshmaiah, M., Afrin, S., Malladi, R.P., Elkoun, S., Robert, M., Ansari, M.A., Svedberg, A., and Karim, Z. 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