Fabrication of polylactide with high-content, ordered, and continuous transcrystallinity via multilayered two-dimensional interface

Li-shen, Wang; Yu, Guiying; Zhu, Yifan; Li, Chunhai; Li, Jiang; Guo, Shaoyun

doi:10.1016/j.matdes.2021.109687

Cited by 5 publications

(6 citation statements)

References 39 publications

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“…The area percentage of the auxiliary material at the exit of the die was 9.84%, slightly larger than that at the entrance. These results suggest a slight interfacial movement within the die [ 2 , 15 ].…”

Section: Resultsmentioning

confidence: 99%

“…The polymer coextrusion process [ 1 ] is a type of extrusion process that can be used to manufacture polymer composites with different structures, complicated functional areas, or multiple colors. Coextrusion technology is widely used for composite films [ 2 ], sheets, pipes [ 3 ], and profiles [ 4 ]. For medical products, the coextrusion is used to produce single-lumen or multi-lumen catheters [ 5 ], such as balloon dilatation catheters, stent implantation catheters, urinary catheters, and hemodialysis catheters.…”

Section: Introductionmentioning

confidence: 99%

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Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

2023

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The main challenge in a polymer coextrusion process is to have a good die design prior to the process, which can minimize the geometric errors that are caused by extrusion swell and interface motion. For this purpose, a coupling method of optimization and inverse design for a coextrusion die was studied for a medical striped catheter. In the study, the main material was thermoplastic polyurethane (TPU), and the auxiliary material was TPU filled with 30 wt% barium sulfate. An overall optimization design method was used to optimize the geometry of the extrusion die channel for the striped catheter, which had a complex geometry. In the global optimization process, the local inverse design method was used to design the inlet of the auxiliary material. The non-linear programming by quadratic Lagrangian (NLPQL) algorithm was used to obtain the optimal geometric solution of the coextrusion die runner. The experimental verification results showed that the coupling method for coextrusion die design improved the design efficiency of the coextrusion die remarkably. The value of the objective function, which was used to measure the geometric error of the product, was reduced by 72.3% compared with the initial die design.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

2023

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“…Therefore, investigators have sought to raise the crystalline nucleation point by introducing conventional inorganic nucleating agents like talc [ 23 ] and graphite [ 24 ]. These agents serve to help nucleation or accelerate the growth of spherical crystals [ 7 , 25 ]. Wang et al [ 25 ] co-extruded PLA filled with nucleating agent TMC200 to establish a multilayered structure.…”

Section: Introductionmentioning

confidence: 99%

“…These agents serve to help nucleation or accelerate the growth of spherical crystals [ 7 , 25 ]. Wang et al [ 25 ] co-extruded PLA filled with nucleating agent TMC200 to establish a multilayered structure. As a result, this induced a high content of continuous and ordered transverse crystals.…”

Section: Introductionmentioning

confidence: 99%

Crystallinity, Rheology, and Mechanical Properties of Low-/High-Molecular-Weight PLA Blended Systems

Yang,

2023

Molecules

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As semi-crystalline polyester (lactic acid) (PLA) is combined with other reinforcing materials, challenges such as phase separation, environmental pollution, and manufacturing difficulties could hinder the benefits of PLA, including complete biodegradability and strong mechanical properties. In the present investigation, melt blending is utilized to establish a mixture of low- and high-molecular-weight polylactic acids (LPLA and HPLA). The crystallinity, rheology, and mechanical properties of the combination were analyzed using rotational rheometry, differential scanning calorimetry, X-ray diffraction, polarized optical microscopy, scanning electron microscopy, and universal testing equipment. The results demonstrate compatibility between LPLA and HPLA. Moreover, an increase in LPLA concentration leads to a decrease in the crystallization rate, spherulite size, fractional crystallinity, and XRD peak intensity during isothermal crystallization. LPLA acts as a diluent during isothermal crystallization, whereas HPLA functions as a nucleating agent in the non-isothermal crystallization process, promoting the growth of LPLA crystals and leading to co-crystallization. The blended system with a 5% LPLA mass fraction exhibits the highest tensile strength and enhances rheological characteristics. By effectively leveraging the relationship between various molecular weights of PLA’s mechanical, rheological, and crystallization behavior, this scrutiny improves the physical and mechanical characteristics of the material, opening up new opportunities.

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“…Academic research on nanolayer films can be broadly summarized into three aspects: (i) interfacial phenomena: the two-dimensional (2D) interfacial region takes a considerable, even a predominate ratio out of the bulk of nanolayer films, which is valuable to study the interfacial phenomena including interfacial diffusion, 10,11 interfacial reaction, 12,51 interfacial epitaxial crystallization, 13,14,50 interfacial slip 15 and instabilities during flow, 11 interfacial adhesion and debonding, 16 and so on; (ii) confined phase transition and molecular relaxation behaviors: the confined layer space generated by the alternating nanolayer in the nanolayer film can be used to study the confined phase transitions such as confined crystallization, 17,18 confined glass transition, 19 and confined phase separation, 20 as well as the confined damping and confined chain relaxation; 21 and (iii) unequaled performances conferred by the superlattice nanolayer configuration such as advanced optical performances 22,23 and outstanding mechanical and gas barrier performance. 3 Many methodologies have been developed to produce nanolayer films so far, including layer-by-layer multilayers from polymer solutions or melts, 3,24 self-assembly of block copolymers, 25 and the cast film of nanolayer coextrusion.…”

Section: ■ Introductionmentioning

confidence: 99%

Development of Nanolayer Blown Film Technology

Hong

Ran

et al. 2022

Ind. Eng. Chem. Res.

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Nanolayer films are monolithic films including 30−1000 periodic alternating layers, each layer having a thickness of 20−5000 nm. Owing to the superlattice multilayer configuration, nanolayer films usually show outstanding mechanical, barrier, and optical properties and thus have broad application prospects in the film industry. This work develops a nanolayer blown technology by combining a blown die and layer multiplication concepts, which can produce blown films with 1000+ layers and thickness below 10 μm. In detail, planar nanolayers were first produced via a flat-die layer multiplication coextrusion, wrapped into annular profiles by using a well-designed custom-made blown die, and then were blown up into the bubble to obtain the nanolayer films. Experimental verifications show that nanolayer films with 1000+ layers can be easily fabricated by using this technique. Consequently, this effort may be a breakthrough in blown film technology and thus provides some positive effects on the film industry.

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Fabrication of polylactide with high-content, ordered, and continuous transcrystallinity via multilayered two-dimensional interface

Cited by 5 publications

References 39 publications

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

Improved Optimization of a Coextrusion Die with a Complex Geometry Using the Coupling Inverse Design Method

Crystallinity, Rheology, and Mechanical Properties of Low-/High-Molecular-Weight PLA Blended Systems

Development of Nanolayer Blown Film Technology

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