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Scalable Continuous Manufacturing Process of Stereocomplex PLA by Twin-Screw Extrusion. Polymers (Basel) 2023; 15:polym15040922. [PMID: 36850205 PMCID: PMC9965968 DOI: 10.3390/polym15040922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/07/2023] [Accepted: 02/11/2023] [Indexed: 02/15/2023] Open
Abstract
A scalable continuous manufacturing method to produce stereocomplex PLA was developed and optimized by melt-blending a 1:1 blend of high molecular weight poly(L-lactide) (PLLA) and high molecular weight poly(D-lactide) (PDLA) in a co-rotating twin-screw extruder. Thermal characteristics of stereocomplex formation were characterized via DSC to identify the optimal temperature profile and time for processing stereocomplex PLA. At the proper temperature window, high stereocomplex formation is achieved as the twin-screw extruder allows for alignment of the chains; this is due to stretching of the polymer chains in the extruder. The extruder processing conditions were optimized and used to produce >95% of stereocomplex PLA conversion (melting peak temperature Tpm = 240 °C). ATR-FTIR depicts the formation of stereocomplex crystallites based on the absorption band at 908 cm-1 (β helix). The only peaks observed for stereocomplex PLA's WAXD profile were at 2θ values of 12, 21, and 24°, verifying >99% of stereocomplex formation. The total crystallinity of stereocomplex PLA ranges from 56 to 64%. A significant improvement in the tensile behavior was observed in comparison to the homopolymers, resulting in a polymer of high strength and toughness. These results lead us to propose stereocomplex PLA as a potential additive/fiber that can reinforce the material properties of neat PLA.
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Stocco E, Porzionato A, De Rose E, Barbon S, Caro RD, Macchi V. Meniscus regeneration by 3D printing technologies: Current advances and future perspectives. J Tissue Eng 2022; 13:20417314211065860. [PMID: 35096363 PMCID: PMC8793124 DOI: 10.1177/20417314211065860] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/24/2021] [Indexed: 01/10/2023] Open
Abstract
Meniscal tears are a frequent orthopedic injury commonly managed by conservative
strategies to avoid osteoarthritis development descending from altered
biomechanics. Among cutting-edge approaches in tissue engineering, 3D printing
technologies are extremely promising guaranteeing for complex biomimetic
architectures mimicking native tissues. Considering the anisotropic
characteristics of the menisci, and the ability of printing over structural
control, it descends the intriguing potential of such vanguard techniques to
meet individual joints’ requirements within personalized medicine. This
literature review provides a state-of-the-art on 3D printing for meniscus
reconstruction. Experiences in printing materials/technologies, scaffold types,
augmentation strategies, cellular conditioning have been compared/discussed;
outcomes of pre-clinical studies allowed for further considerations. To date,
translation to clinic of 3D printed meniscal devices is still a challenge:
meniscus reconstruction is once again clear expression of how the integration of
different expertise (e.g., anatomy, engineering, biomaterials science, cell
biology, and medicine) is required to successfully address native tissues
complexities.
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Affiliation(s)
- Elena Stocco
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria, Padova, Italy
| | - Andrea Porzionato
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria, Padova, Italy
| | - Enrico De Rose
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
| | - Silvia Barbon
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria, Padova, Italy
| | - Raffaele De Caro
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria, Padova, Italy
| | - Veronica Macchi
- Department of Neuroscience, Section of Human Anatomy, University of Padova, Padova, Italy
- L.i.f.e.L.a.b. Program, Consorzio per la Ricerca Sanitaria, Padova, Italy
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Dimonie D, Mathe S, Iftime MM, Ionita D, Trusca R, Iftimie S. Modulation of the PLLA Morphology through Racemic Nucleation to Reach Functional Properties Required by 3D Printed Durable Applications. MATERIALS (BASEL, SWITZERLAND) 2021; 14:6650. [PMID: 34772174 PMCID: PMC8588124 DOI: 10.3390/ma14216650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 10/29/2021] [Accepted: 10/31/2021] [Indexed: 11/16/2022]
Abstract
This paper presents an alternative for enhancing the durability of poly (L-lactide) (PLLA) by racemic nucleation following stereo-complexation with a selected poly (D-lactide) (PLDA). The compounds are obtained by melt blending of a PLLA grade, previously designed for 3D printing but with a low heat deflection temperature and impact resistance, with grades of PLDA differing in their molecular weight (Mw), D-lactide content (DS) and concentration. Our method considered how to reveal the racemic nucleation caused by stereo-complexation and its influence on functional properties. The FTIR study we performed showed that, depending on Mw, DS and concentration of the stereo-complexer (PDLA) used, bigger or smaller spectral changes can occur. The stereo-complexation was confirmed by the DSC analysis and, for the selected compound, by the POM, SEM, AFM microscopies, functional property and shapeability as 3D printing filaments. All the obtained results sustain the idea that, if a PLLA with Mw of 4.5 × 104 g·mol-1 is modified with PDLA with a medium Mw of 11.6 × 104 g·mol-1, medium DS of 4% and 1% concentration, a racemic nucleation is possible. It produces a racemic polylactic acid (PDLLA) with improved durability and good shapeability as 3D printing filaments. These results are explicable if the dependence of the intermolecular interactions appears between the PLLA and stereo-complexer PDLA. To enlarge the durable applicability of racemic polylactic acid (PDLLA), future research should identify other parameters controling the PLA stereo-complexing as the intensifying the mobility of the macromolecules, the finding of the optimal recemic cristalization window.
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Affiliation(s)
- Doina Dimonie
- National Institute for Research and Development in Chemistry and Petrochemistry, 202 Splaiul Independentei, 060021 Bucharest, Romania;
| | - Silvia Mathe
- Doctoral School “Applied Chemistry and Materials Science”, Politehnica University of Bucharest, 1-7 Gheorghe Polizu, 011061 Bucharest, Romania
| | - Manuela Maria Iftime
- “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (M.M.I.); (D.I.)
| | - Daniela Ionita
- “Petru Poni” Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, 700487 Iasi, Romania; (M.M.I.); (D.I.)
| | - Roxana Trusca
- Department of Science and Engineering of Oxide Materials and Nanomaterials, Politehnica University of Bucharest, 1-7 Gheorghe Polizu, 011061 Bucharest, Romania;
| | - Sorina Iftimie
- Department of Electricity and Magnetism, Solid-State Physics, and Biophysics, Faculty of Physics, University of Bucharest, 405 Atomistilor, 077125 Magurele, Romania;
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Zhu Q, Chang K, Qi L, Li X, Gao W, Gao Q. Surface Modification of Poly(l-lactic acid) through Stereocomplexation with Enantiomeric Poly(d-lactic acid) and Its Copolymer. Polymers (Basel) 2021; 13:1757. [PMID: 34072033 PMCID: PMC8198229 DOI: 10.3390/polym13111757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Revised: 05/21/2021] [Accepted: 05/24/2021] [Indexed: 11/16/2022] Open
Abstract
Poly(l-lactic acid) with high molecular weight was used to prepare PLLA films by means of the solvent casting technique. Poly(d-lactic acid) (PDLA) and poly(d-lactic acid-co-glucose) copolymer (PDLAG) with a low molecular weight were synthesized from d-lactic acid and glucose through melt polycondensation. PLLA films were immersed in PDLA or PDLAG solution to prepare surface-modified PLLA films. The modified PLLA film presented stereocomplex crystal (SC) on its surface and homogeneous crystals (HC) in its bulk. The HC structure and surface morphology of modified PLLA films were obviously damaged by PDLA or PDLAG solution. With increasing immersion time, the PLLA films modified by PDLA decreased both the HC and SC structure, while the PLLA films modified by PDLAG increased the SC structure and decreased the HC structure. Hydrophilic glucose residues of PDLAG on the surface would improve the hydrophilicity of surface-modified PLLA films. Moreover, the hydrophilicity of glucose residues and the interaction of glucose residues with lactic acid units could retard HC destruction and SC crystallization, so that PLLA films modified by PDLAG possessed lower melting temperatures of HC and SC, the crystallinity of SC and the water contact angle, compared with PDLAG-modified PLLA films. The SC structure could improve the heat resistance of modified PLLA film, but glucose residues could block crystallization to promote the thermal degradation of PLA materials. The surface modification of PLLA films will improve the thermal stability, hydrophilicity and crystallization properties of PLA materials, which is essential in order to obtain PLA-based biomaterials.
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Affiliation(s)
- Qianjin Zhu
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
| | - Kaixin Chang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
| | - Liyan Qi
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
| | - Xinyi Li
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
| | - Woming Gao
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
| | - Qinwei Gao
- College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; (Q.Z.); (K.C.); (L.Q.); (X.L.); (W.G.)
- Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China
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