共查询到12条相似文献,搜索用时 0 毫秒
1.
Hoelscher Fernanda Cardoso Priscilla B. Candiotto Graziâni Guindani Camila Feuser Paulo Araújo Pedro H. H. Sayer Claudia 《Journal of Polymers and the Environment》2021,29(11):3668-3678
Journal of Polymers and the Environment - Biodegradability is a key feature for the application of polymeric devices in medicine. This study reports an experimental and theoretical study of the... 相似文献
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Nuria Burgos Daniel Tolaguera Stefano Fiori Alfonso Jiménez 《Journal of Polymers and the Environment》2014,22(2):227-235
The use of fully bio-based and biodegradable materials for massive applications, such as food packaging, is an emerging tendency in polymer research. But the formulations proposed in this way should preserve or even increase the functional properties of conventional polymers, such as transparency, homogeneity, mechanical properties and low migration of their components to foodstuff. This is not always trivial, in particular when brittle biopolymers, such as poly(lactic acid) (PLA), are considered. In this work the formulation of innovative materials based on PLA modified with highly compatible plasticizers, i.e. oligomers of lactic acid (OLAs) is proposed. Three different synthesis conditions for OLAs were tested and the resulting additives were further blended with commercial PLA obtaining transparent and ductile materials, able for films manufacturing. These materials were tested in their structural, thermal and tensile properties and the best formulation among the three materials was selected. OLA with molar mass (Mn) around 1,000 Da is proposed as an innovative and fully compatible and biodegradable plasticizer for PLA, able to replace conventional plasticizers (phthalates, adipates or citrates) currently used for films manufacturing in food packaging applications. 相似文献
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Al-Qahtani Salhah D. Alnoman Rua B. Snari Razan M. Aljuhani Enas Bayazeed Abrar Qurban Jihan El-Metwaly Nashwa M. 《Journal of Polymers and the Environment》2022,30(7):3107-3118
Journal of Polymers and the Environment - Novel phenothiazine fluorophore containing two tricyanofuran-vinyl groups [tricyanofuran(TCF)-bearing phenothiazine(P); TCFP] as cyanide anion receptors... 相似文献
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Erceg Tamara Brakus Gaja Stupar Alena Cvetinov Miroslav Hadnađev Miroslav Ristić Ivan 《Journal of Polymers and the Environment》2022,30(9):3737-3760
Journal of Polymers and the Environment - The paper presents the synthesis of hydrogels via free-radical polymerization, based on Chitosan (CS) grafted with Acrylic acid (AA), using a two-step... 相似文献
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A Comparison of Modified and Unmodified Cellulose Nanofiber Reinforced Polylactic Acid (PLA) Prepared by Twin Screw Extrusion 总被引:1,自引:0,他引:1
Mehdi Jonoobi Aji P. Mathew Mahnaz M. Abdi Majid Davoodi Makinejad Kristiina Oksman 《Journal of Polymers and the Environment》2012,20(4):991-997
The goal of this work was to evaluate the effect of chemical modification of cellulose nanofibers (CNF) on the properties of polylactic acid (PLA) nanocomposites. Acetylated nanofibers (ACNF), with degree of substitution 1.07, were isolated from acetylated kenaf fibers by mechanical treatments. Acetylated nanofibers showed more hydrophobic properties compared to non-acetylated ones. The results showed that both crystallinity and thermal stability of acetylated nanofibers were lower than non-acetylated ones. The nanocomposites were prepared by premixing two PLA master batches, one with a high concentration of ACNF and the second with CNF. These were diluted to final concentrations (5?wt%) during the extrusion. The morphology studies of PLA and its nanocomposites showed nanofiber aggregates in both materials. The results showed that the tensile and dynamic mechanical properties were enhanced for both acetylated and non-acetylated nanocomposites compared to the neat PLA matrix while no significant improvement was observed for the acetylated nanocomposites compared to non-acetylated ones. However, the storage modulus increased slightly for acetylated nanocomposites compared to non-acetylated ones. 相似文献
8.
Linbo Wu Yan Zhang Hong Fan Zhiyang Bu Bo-Geng Li 《Journal of Polymers and the Environment》2008,16(1):68-73
As an attempt to synthesize new biodegradable polymers from renewable cellulose resources, melt polycondensation of 5-hydroxylevulinic
acid (5-HLA) was reported for the first time. The resulting product, poly(5-hydroxylevulinic acid) (PHLA), was synthesized
and characterized with GPC, FTIR, 1H NMR and DSC. The in vitro degradation behaviors in phosphate-buffered saline (PBS) and in deionized water (DW) were also
examined. The molecular weight of PHLA is not high (several 1,000s), but it possesses unordinary high glass transition temperature
(as high as 120 °C). This is very different from existing aliphatic polyesters that usually have T
gs lower than 60 °C. The high T
g is attributed to the formation of inter- and/or intramolecular hydrogen bonds due to a characteristic keto–enol tautomerism
equilibrium in the polymer structure. PHLA readily degraded hydrolytically in aqueous media. 相似文献
9.
The utilization of captured CO2 as a part of the CO2 capture and storage system to produce biopolymers could address current environmental issues such as global warming and depletion of resources. In this study, the effect of feeding strategies of CO2 and valeric acid on cell growth and synthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] in Cupriavidus necator was investigated to determine the optimal conditions for microbial growth and biopolymer accumulation. Among the studied CO2 concentrations (1–20 %), microbial growth and poly(3-hydroxybutyrate) accumulation were optimal at 1 % CO2 using a gas mixture at H2:O2:N2 = 7:1:91 % (v/v). When valeric acid was fed together with 1 % CO2, (R)-3-hydroxyvalerate synthesis increased with increasing valeric acid concentration up to 0.1 %, but (R)-3-hydroxybutyrate synthesis was inhibited at >0.05 % valeric acid. Sequential addition of valeric acid (0.05 % at Day 0 followed by 0.025 % at Day 2) showed an increase in 3HV fraction without inhibitory effects on 3HB synthesis during 4 d accumulation period. The resulting P(3HB-co-3HV) with 17–32 mol % of 3HV is likely to be biocompatible. The optimal concentrations and feeding strategies of CO2 and valeric acid determined in this study for microbial P(3HB-co-3HV) synthesis can be used to produce biocompatible P(3HB-co-3HV). 相似文献
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Removal of Cinnamic Acid Derivatives from Aqueous Effluents by Fenton and Fenton-like Processes as an Alternative to Direct Biological Treatment 总被引:2,自引:0,他引:2
Dionissios Mantzavinos 《Water, Air, & Soil Pollution: Focus》2003,3(3):211-221
The removal of various phenolic acids (p-coumaric, caffeic and ferulic acids), typically found in wastewaters of agricultural origin, from model effluents by chemical and biological means has been investigated. Chemical oxidation processes comprising hydrogen peroxide and a homogeneous or heterogeneous copper or iron catalyst were employed over a wide range of experimental conditions. Chemical oxidation is capable of removing most of the total organic carbon initially present in the effluent at relatively mild treatment conditions (i.e. reaction times up to 120 min and temperatures up to 80°C), while removal rates generally increase with increasing temperature, H2O2 and catalyst concentrations. The anaerobic degradability and toxicity of p-coumaric acid has been assessed using the biochemical methane potential and anaerobic toxicity assay respectively. p-Coumaric acid, at concentrations below about 1 g/L, is not toxic against methanogens and slowly degrades over a period of about 35 days at 35°C. In light of this, chemical oxidation may provide a promising alternative to direct biological treatment for either the partial or complete removal of phenolic acids at reasonable treatment times; the implications for wastewater treatment are discussed. 相似文献
11.
Rejek M. Grzechulska-Damszel J. Schmidt B. 《Journal of Polymers and the Environment》2021,29(11):3660-3667
Journal of Polymers and the Environment - Degussa P25 titanium dioxide/chitosan composites (P25/CS) were prepared using three different methods and two different chitosan materials. The obtained... 相似文献
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Pablo Jiménez-Bonilla Jessica Salas-Arias Marianelly Esquivel Jose Roberto Vega-Baudrit 《Journal of Polymers and the Environment》2014,22(3):393-397
In Costa Rica, a lot of pineapple (Ananas comosus) and banana (Musa AAA) agroindustrial residues are generated each year. These residues can be used to obtain l-lactic acid by fermentation, ultrafiltration and electrodialysis. Poly(l-lactic acid) (PLLA) is a biodegradable and renewable polyester with many industrial and biomedical applications. There is a growing interest to improve the energetic efficiency of the synthesis of PLLA, because the main issue to produce this polymer is the high productive cost compared with petrochemical traditional commodities. In this research, the synthesis of PLLA through two different techniques was compared: microwave-assisted and conventional heating. On microwave synthesis the best results were obtained using lower temperatures and lower reaction times than the conventional heated synthesis. The reaction time was reduced from 15 h by conventional heating to 4.5 h using microwave-assisted synthesis. 相似文献