Progress in the Preparation, Properties, and Applications of PLA and Its Composite Microporous Materials by Supercritical CO2: A Review from 2020 to 2022

Peng, Kangming; Mubarak, Suhail; Diao, Xuefeng; Cai, Zewei; Zhang, Chen; Wang, Jianlei; Wu, Lixin

doi:10.3390/polym14204320

Cited by 19 publications

(17 citation statements)

References 112 publications

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“…Therefore, global efforts are being made to create green polymers from renewable resources. Environmentally friendly plastics provide a possible solution to the above problems [ 2 ]. Polymer foam is a polymer/gas composite material with a polymer matrix, which offers the advantages of a lower charge, light weight, high impact strength, and good heat and sound insulation; thus, it is widely used in packaging, construction, medical applications, sound insulation, earthquake resistance, and electromagnetic shielding fields [ 3 , 4 , 5 ].…”

Section: Introductionmentioning

confidence: 99%

High-Strength Bio-Degradable Polymer Foams with Stable High Volume-Expansion Ratio Using Chain Extension and Green Supercritical Mixed-Gas Foaming

Long

Shaoyu

et al. 2023

Polymers

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The preparation of biodegradable polymer foams with a stable high volume-expansion ratio (VER) is challenging. For example, poly (butylene adipate-co-terephthalate) (PBAT) foams have a low melt strength and high shrinkage. In this study, polylactic acid (PLA), which has a high VER and crystallinity, was added to PBAT to reduce shrinkage during the supercritical molded-bead foaming process. The epoxy chain extender ADR4368 was used both as a chain extender and a compatibilizer to mitigate the linear chain structure and incompatibility and improve the foamability of PBAT. The branched-chain structure increased the energy-storage modulus (G’) and complex viscosity (η*), which are the key factors for the growth of cells, by 1–2 orders of magnitude. Subsequently, we innovatively used the CO2 and N2 composite gas method. The foam-shrinkage performance was further inhibited; the final foam had a VER of 23.39 and a stable cell was obtained. Finally, after steam forming, the results showed that the mechanical strength of the PBAT/PLA blended composite foam was considerably improved by the addition of PLA. The compressive strength (50%), bending strength, and fracture load by bending reached 270.23 kPa, 0.36 MPa, and 23.32 N, respectively. This study provides a potential strategy for the development of PBAT-based foam packaging materials with stable cell structure, high VER, and excellent mechanical strength.

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Section: Introductionmentioning

confidence: 99%

High-Strength Bio-Degradable Polymer Foams with Stable High Volume-Expansion Ratio Using Chain Extension and Green Supercritical Mixed-Gas Foaming

Long

Shaoyu

et al. 2023

Polymers

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“…Poly(lactic acid) (PLA) is a synthetic aliphatic polyester produced by the polymerization of lactic acid derived from renewable resources (plants as feedstock), such as agricultural waste and by-products, as a cheap and abundant source of lignocellulosic biomass [ 1 ]. It is extensively tested both at academic and industrial levels due to non-toxic components for its manufacturing as well as its biocompatibility, biodegradability, and/or compostability [ 2 , 3 , 4 , 5 , 6 ]. The emerging bio-based applications of materials coupled with the need of society to replace conventional plastics, as well as regulations that restrict plastic usage, encourage growth in the number of PLA-based products available to consumers.…”

Section: Introductionmentioning

confidence: 99%

“…Although PLA has good properties, including processability, its mass production and utilization are currently restricted due to low melt strength, slow crystallization, poor thermal resistance, brittleness, and/or sensitivity to moisture [ 2 , 5 , 14 , 15 ]. PLA treatment using CO 2 under elevated pressure was suggested to improve material properties, endow material with new functionalities, or prepare material for a specific application [ 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

“…The versatility of CO 2 under an elevated pressure for PLA processing is due to its special properties such as tunable solubility and diffusivity, which significantly increase with the change of CO 2 from gas, liquid, and dense to a supercritical state [ 5 ]. Sc-CO 2 can be dissolved in amorphous and semicrystalline polymers resulting in polymer plasticization, i.e., the increased segmental and chain mobility lowering their resistance to rotation, decrease in crystallization temperature ( T cr ), and decrease in glass transition temperature ( T g ) [ 2 , 5 , 15 , 18 , 19 , 22 ]. The Lewis acid–base interaction between CO 2 and carbonyl groups as well as the C–H∙∙∙O hydrogen bonding facilitate the interaction of PLA with CO 2 under elevated pressure [ 11 , 23 , 24 ].…”

Section: Introductionmentioning

confidence: 99%

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Green Processing of Neat Poly(lactic acid) Using Carbon Dioxide under Elevated Pressure for Preparation of Advanced Materials: A Review (2012–2022)

et al. 2023

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This review provides a concise overview of up-to-date developments in the processing of neat poly(lactic acid) (PLA), improvement in its properties, and preparation of advanced materials using a green medium (CO2 under elevated pressure). Pressurized CO2 in the dense and supercritical state is a superior alternative medium to organic solvents, as it is easily available, fully recyclable, has easily tunable properties, and can be completely removed from the final material without post-processing steps. This review summarizes the state of the art on PLA drying, impregnation, foaming, and particle generation by the employment of dense and supercritical CO2 for the development of new materials. An analysis of the effect of processing methods on the final material properties was focused on neat PLA and PLA with an addition of natural bioactive components. It was demonstrated that CO2-assisted processes enable the control of PLA properties, reduce operating times, and require less energy compared to conventional ones. The described environmentally friendly processing techniques and the versatility of PLA were employed for the preparation of foams, aerogels, scaffolds, microparticles, and nanoparticles, as well as bioactive materials. These PLA-based materials can find application in tissue engineering, drug delivery, active food packaging, compostable packaging, wastewater treatment, or thermal insulation, among others.

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“…Among bio-based polymers, poly(L-lactic acid) or poly(L-lactide) (PLLA) has received the most attention because of its biodegradability, biocompatibility, processability, and possibilities for production scale-up [ 3 , 4 , 5 ]. PLLA has been extensively investigated for medical, pharmaceutical, packaging, agricultural, automotive, and electronic applications [ 1 , 2 , 5 , 6 , 7 ]. The main limitation in the use of PLLA is that it is less flexible [ 8 ].…”

Section: Introductionmentioning

confidence: 99%

Phase Morphology, Mechanical, and Thermal Properties of Calcium Carbonate-Reinforced Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastics

2023

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Poly(L-lactide) (PLLA) is a promising candidate as a bioplastic because of its non-toxicity and biodegradability. However, the low flexibility of PLLA limits its use in many applications. Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) (PLLA-b-PEG-b-PLLA) block copolymer is of interest for bioplastic applications due to its superior flexibility compared to PLLA. The aim of this work is to modify PLLA-b-PEG-b-PLLA using a low-cost calcium carbonate (CaCO3) filler to improve material properties compared to PLLA/CaCO3 composites. The addition of CaCO3 enhanced the crystallinity and thermal stability for the PLLA-b-PEG-b-PLLA matrix but not for the PLLA matrix, as determined by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), and thermogravimetric analysis (TGA). Phase morphology investigation using scanning electron microscopy (SEM) revealed that the interfacial adhesion between PLLA-b-PEG-b-PLLA and CaCO3 was stronger than between PLLA and CaCO3. Additionally, tensile testing was carried out to determine the mechanical properties of the composites. With the addition of CaCO3, the tensile stress and Young’s modulus of the PLLA-b-PEG-b-PLLA matrix were increased, whereas these properties of the PLLA matrix were significantly decreased. Thus, CaCO3 shows great promise as an inexpensive filler that can induce nucleation and reinforcing effects for PLLA-b-PEG-b-PLLA bioplastics.

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Progress in the Preparation, Properties, and Applications of PLA and Its Composite Microporous Materials by Supercritical CO2: A Review from 2020 to 2022

Cited by 19 publications

References 112 publications

High-Strength Bio-Degradable Polymer Foams with Stable High Volume-Expansion Ratio Using Chain Extension and Green Supercritical Mixed-Gas Foaming

High-Strength Bio-Degradable Polymer Foams with Stable High Volume-Expansion Ratio Using Chain Extension and Green Supercritical Mixed-Gas Foaming

Green Processing of Neat Poly(lactic acid) Using Carbon Dioxide under Elevated Pressure for Preparation of Advanced Materials: A Review (2012–2022)

Phase Morphology, Mechanical, and Thermal Properties of Calcium Carbonate-Reinforced Poly(L-lactide)-b-poly(ethylene glycol)-b-poly(L-lactide) Bioplastics

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