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Catalytic Cracking of polylactic acid to Acrylic acid

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Chinese Journal of Chemistry 2023年第17期41卷 2071-2076页

作者： Yuchen Jiao Meng Wang Ding Ma Beijing National Laboratory for Molecular Sciences New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

Comprehensive Summary,As a typical type of sustainable plastic,polyesters can be recycled or upcycled into value-added chemicals in a variety of ***,excess reagents are required for most of the depolymerization and upcycling processes,causing the emission of environmental pollutants and the waste of chemical *** we demonstrate a one-pot catalytic process to directly crack polylactic acid into acrylic acid by acid catalyst with the assistance of an ionic liquid,*** acid is attacked by the Br–from Bu4PBr and the H+from acid to form oligomers containing Br or acryloyl group,and these oligomers serve as intermediates to produce acrylic acid during their mutual *** acrylic acid is vaporized directly from the reactor and obtained in a collector with a selectivity around 90%when polylactic acid is fully *** green process shows great advantages in atom economy compared to the conventional recycling/upcycling methods for polyesters,in addition.

关键词： polylactic acid Acrylic acid Atom economy Upcycling lonic liquid Commodity polymers Plastics Green chemistry

Study on Dyeing of a Novel,Pro-environment polylactic acid (PLA) Fiber Yarn

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Journal of Donghua University(English Edition) 2008年第5期25卷 601-606页

作者：傅科杰闵洁李峥嵘杨力生 Ningbo Entry-exit Inspection and Quarantine Bureau of P.R.C College of Chemistry and Chemical Engineering Donghua University

Seventeen disperse dyes including anthraquinone, azo, methine, nitro, and quinoline dyes were applied to dye the polylactic acid （PLA） yarns at different conditions, and the dyebath exhaustion was determined. The result shows that C.I. disperse red 167, C.I. disperse orange 30, and C.I. disperse blue 284 have dye-uptakes greater than 80%. Therefore, they can be used as the three principal dyes for PLA yams. The experiment discovered that the dyes, because of their Monoazo and ester group contents, have a higher dye-uptake for the PLA fiber. The research on the optimization of dyeing techniques suggests that PLA yarn can obtain a high level of dyeing effectiveness at the following conditions： pH 4- 5, dyeing temperture 110℃ for 30- 40 min. Color fastness to perspiration, and waterwashing fastness increased 1 - 1.5 by the addition of the abstergent FB during the reduction clearing.

关键词： polylactic acid disperse dye dye-uptake color fastness reduction clearing

Isolation of Microcrystalline Cellulose from Wood and Fabrication of polylactic acid(PLA)Based Green Biocomposites

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Journal of Renewable Materials 2024年第8期12卷 1455-1474页

作者： Selwin Maria Sekar Rajini Nagarajan Ponsuriyaprakash Selvakumar Ismail Sikiru Oluwarotimi Kumar Krishnan Faruq Mohammad Mohammed Rafi Shaik Nadir Ayrilmis Department of Mechanical Engineering Kalasalingam Academy of Research and EducationKrishnankoil626126India Department of Mechanical Engineering SSM Institute of Engineering and TechnologyDindigul624002India Department of Engineering Centre for Engineering ResearchSchool of PhysicsEngineering and Computer ScienceUniversity of HertfordshireHatfieldAL109ABUK INTI International University Persiaran Perdana BBNNilai71800Malaysia Department of Chemistry College of ScienceKing Saud UniversityP.O.Box 2455Riyadh11451Kingdom of Saudi Arabia Department of Wood Mechanics and Technology Faculty of ForestryIstanbul University–CerrahpasaBahcekoySariyerIstanbul34473Turkey

An innovative microcrystalline cellulose(MCC)natural fibre powder-reinforced PLA biocomposite was investigated using the hand lay-up *** polymer matrix composite(PMC)samples were prepared by varying the weight percentages(wt.%)of both PLA matrix and MCC reinforcement:pure PLA/100:0,90:10,80:20,70:30,60:40 and 50:50 wt.%,*** the results obtained,MCC powder,with its impressive aspect ratio,proved to be an ideal reinforcement for the PLA,exhibiting exceptional mechanical *** was evident that the 80:20 wt.%biocomposite sample exhibited the maximum improvement in the tensile,flexural,notched impact,compressive strength and hardness by 28.85%,20.00%,91.66%,21.53%and 35.82%,respectively compared to the pure PLA ***,during the thermogravimetric analysis(TGA),the same 80:20 wt.%biocomposite sample showed a minimum weight loss of 20%at 400℃,among *** morphological study using Field Emission Scanning Electron Microscopy(FE-SEM)revealed that the uniform distribution of cellulose reinforcement in the PLA matrix actively improved the mechanical properties of the biocomposites,especially the optimal 80:20 wt.%***,it was evident that the optimal PLA/cellulose biocomposite sample could be a suitable and alternative sustainable,environmentally friendly and biodegradable material for semi/structural applications,replacing synthetic and traditional components.

关键词： polylactic acid micro crystalline cellulose biocomposite characterizations FESEM environmental pollution

Fabrication of magnesium-doped porous polylactic acid microsphere for bone regeneration

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Biomaterials Translational 2023年第4期4卷 280-290页

作者： Ziwei Tao Ziyang Yuan Dong Zhou Lang Qin Lan Xiao Shihao Zhang Changsheng Liu Jinzhong Zhao Yulin Li Engineering Research Centre for Biomedical Materials of Ministry of Education Key Laboratory for Ultrafine Materials of Ministry of EducationSchool of Materials Science and EngineeringEast China University of Science and TechnologyShanghaiChina Department of Sports Medicine Shanghai Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University School of MedicineShanghaiChina School of Chemistry and Chemical Engineering Nanchang UniversityNanchangJiangxi ProvinceChina School of Mechanical Medical and Process EngineeringCenter of Biomedical TechnologyQueensland University of TechnologyBrisbaneAustralia Wenzhou Institute of Shanghai University WenzhouZhejiang ProvinceChina

Biodegradable polymer microspheres that can be used as drug carriers are of great importance in biomedical applications,however,there are still challenges in controllable preparation of microsphere surface morphology and improvement of *** this paper,firstly,poly(L-lactic acid)(PLLA)was synthesised by ring-opening polymerisation under anhydrous anaerobic conditions and further combined with the emulsion method,biodegradable PLLA microspheres(PM)with sizes ranging from 60-100μm and with good sphericity were *** addition,to further improve the surface morphology of PLLA microspheres and enhance their bioactivity,functionalised porous PLLA microspheres loaded with magnesium oxide(MgO)/magnesium carbonate(MgCO_(3))(PMg)were also prepared by the emulsion *** results showed that the loading of MgO/MgCO_(3)resulted in the formation of a porous structure on the surface of the microspheres(PMg)and the dissolved Mg^(2+)could be released slowly during the degradation of *** vitro cellular experiments demonstrated the good biocompatibility of PM and PMg,while the released Mg^(2+)further enhanced the anti-inflammatory effect and osteogenic activity of *** PMg not only show promise for controlled preparation of drug carriers,but also have translational potential for bone regeneration.

关键词： magnesium ion osteogenesis polylactic acid porous microspheres

Thermal Decomposition and Kinetics of Mixtures of polylactic acid and Biomass during Copyrolysis

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Chinese Journal of Chemical Engineering 2008年第6期16卷 929-933页

作者：王刚李爱民 Key Laboratory of Industrial Ecology and Environmental Engineering MOE School of Environmental & Biological Science & Technology Dalian University of Technology Dalian 116024 China

Thermal decomposition of polylactic acid （PLA） was studied in the presence of pine wood sawdust （PS）, walnut shell （WS）, corncob （CC） in order to understand the pyrolytic behavior of these components occurring in waste. A thermogravimetric analyzer （TGA） was applied for monitoring the mass loss profiles under heating rate of 10℃·min^-1. Results obtained from this comprehensive investigation indicated that PLA was decomposed in the temperature range 300 -372℃, whereas the thermal degradation temperature of biomass is 183-462℃. The difference of mass loss （AW） between experimental and theoretical ones, calculated as algebraic sums of those from each separated component, is about 17%-46% at 300-400℃. These experimental results indicated a significant synergistic effect during PLA and biomass copyrolysis. Moreover, a kinetic analysis was performed to fit thermogravimetric data, the global processes being considered as one to two consecutive reactions. A reasonable fit to the experimental data was obtained for all materials and their blends.

关键词： biomass kinetics polylactic acid copyrolysis

Properties enhancement of antimicrobial chitosan-deposited polylactic acid films via cold plasma treatment

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Food and Health 2023年第3期5卷 1-8页

作者： Gui-Yun Chen Tong-Liang Yang Yu-He Wang Shu-Hong Li Ye Chen State Key Laboratory of Food Nutrition and Safety Ministry of EducationCollege of Food Science and BiotechnologyTianjin University of Science&TechnologyTianjin 300457China

The present study aimed to understand the effect of dielectric barrier discharge cold plasma(DBD-CP)technology on the antimicrobial chitosan deposition and the properties enhancement of polylactic acid(PLA)*** results indicated that DBD-CP was an effective method for improving the adhesion and surface hydrophilicity of PLA,facilitating the deposition of chitosan *** modification was attributed to the increased surface roughness,as well as the presence of polar functional groups observed through atomic force microscopy,surface free energy and Fourier transform infrared spectroscopy *** study further revealed that both water resistance and mechanical properties were significantly improved after DBD-CP treatment,which was positively correlated with the amount of chitosan deposited on the PLA *** comprehensive evaluation,the treatment at 75 W was determined as the optimal condition for enhancing the ***,the modified film exhibited strong antimicrobial activity against Staphylococcus ***,the DBD-CP technology could be a promising tool for better utilization of PLA-based materials in the antibacterial food packaging industry.

关键词： dielectric barrier discharge cold plasma polylactic acid chitosan antimicrobial packaging

Green Modification of Cellulose Nanocrystals and Their Reinforcement in Nanocomposites of polylactic acid

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Paper And Biomaterials 2018年第4期3卷 10-18页

作者： Xue Jiang Martin A.Hubbe Jiangsu Engineering and Technology Research Center for Functional Textiles Jiangnan University Key Laboratory of Eco-textiles of Ministry of Education School of Textile and Clothing Jiangnan University State Key Laboratory of Pulp and Paper Engineering South China University of Technology Department of Forest Biomaterials College of Natural Resources North Carolina State University

Cellulose nanocrystals （CNCs） of rod-like shape were prepared from degreased cotton using sulfuric acid hydrolysis. The obtained CNC suspension was neutralized using a sodium hydroxide solution to remove the residual sulfuric acid and improve the thermal stability of the CNC particles. Then, poly（ethylene oxide）（PEO） was employed to modify the nanocrystals through entanglement and physical adsorption. The goal was to further improve the thermal stability and weaken the hydrophilicity of CNCs. Original and modifed CNCs were dosed into a polylactic acid （PLA） matrix to prepare nanocomposites using a hot compression process. Results of the thermogravimetric analysis showed that the initial thermal decomposition temperature of the modifed CNCs showed a 120℃ improvement compared to the original CNCs. That is, the thermal stability of the modified CNCs improved because of their shielding and wrapping by a PEO layer on their surface. Results from scanning electron microscopy and ultraviolet-visible spectrophotometry showed that the compatibility of the modifed CNCs with organic PLA improved, which was attributed to the compatibility of the PEO chains adsorbed on the surface of the CNCs. Finally, the results of tensile tests indicated a significant improvement in terms of breaking strength and elongation at the break point.

关键词： cellulose nanocrystals thermal stability hydrophilicity polylactic acid compatibility nanocomposites

Life Cycle Assessment of Biodegradable polylactic acid(PLA)Plastic Packaging Products—Taking Tianjin,China as a Case Study

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Journal of Resources and Ecology 2022年第3期13卷 428-441页

作者： ZHAO Menglei YANG Zeng ZHAO Jingnan WANG Yan MA Xiaolei GUO Jian Mechanical Engineering College Tianjin University of Science and TechnologyTianjin 300222China Tianjin Key Laboratory of Integrated Design and On-line Monitoring for Light Industry&Food Machinery and Equipment Tianjin 300222China

In this paper, the life cycle assessment(LCA) method is used to evaluate and quantify the energy consumption and environmental impacts of biodegradable polylactic acid(PLA) plastic packaging from the five stages of raw material acquisition, raw material transportation, product production, products use and final disposal. Seven impact categories were selected for the impact analysis: abiotic depletion potential fossil fuels(ADP), global warming potential(GWP), acidification potential(AP), eutrophication potential(EP), photochemical ozone formation potential(POCP), human toxicity potential(HTP), and terrestrial ecotoxicity potential(TETP). The results of the LCA are discussed and the results show that production of products is the highest stage of the environmental impact. Meanwhile, in the entire life cycle, the top three environmental impact categories are GWP, ADP and HTP,which account for 32.63%, 24.83% and 14.01%, respectively. The LCA results show that the environmental impact can be reduced in several ways: reducing the consumption of electricity, increasing the input of new energy, increasing the conversion rate of materials in the production process, using organic and water-soluble fertilizers instead of conventional fertilizers, using environment-friendly fuels and establishing a sound recycling system.

关键词： life cycle assessment energy consumption environmental impacts polylactic acid plastic packaging

Battle against Aging and Folds: Benefit and Risks of the Semi-Permanent Fillers polylactic acid and Calcium Hydroxylapatite

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Advances in Aging Research 2014年第2期3卷 130-141页

作者： Elisabeth Hanf Ursula Gresser Ludwig-Maximilians University of Munich Munich Germany

Background: Semi-permanent fillers are among the most favorable fillers on the market. Through their unique mode of action and its associated lasting aesthetic effect, they take an exceptional position. Objective: To compare the two semi-permanent fillers Poly-L-Lactic acid (PLLA) and calcium hydroxylapatite (CaHA) in reference to the aesthetic result, patient satisfaction and side effects. Methods: Studies on side effects, patient satisfaction and aesthetic results after augmentation with semi-permanent fillers were analyzed. Results: Semi-permanent fillers seem excellently suited for the augmentation of very deep wrinkles particularly in the lower half of the face. In general, high patient satisfaction can be determined with both fillers. Here, the effect from the polylactic acid can be verified for up to two years while no effect could be verified already after one year in a majority of the patients augmented with CaHA. Short-term side effects such as bleedings or erythema in the region of the augmented area have been observed in both fillers during augmentation. The incidence of nodules and granulomas seems significantly higher in augmentations with PLLA compared to CaHA. Rare side effects such as an embolization of a blood vessel caused by the implant have been described for both fillers in case reports. Conclusion: Semi-permanent fillers are superbly suited for wrinkle augmentation. Which filler is the preferred one in what case depends strongly on the individual needs of the patient and the therapist’s experience.

关键词： polylactic acid Calcium Hydroxylapatite Sculptra^(■) Radiesse^(■) Granuloma Semi-Permanent Fillers