scholarly journals The Blending of Poly(glycolic acid) with Polycaprolactone and Poly(l-lactide): Promising Combinations

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2780
Author(s):  
Luca Magazzini ◽  
Sara Grilli ◽  
Seif Eddine Fenni ◽  
Alessandro Donetti ◽  
Dario Cavallo ◽  
...  
Keyword(s):  
Large Scale ◽  
Glycolic Acid ◽  
Barrier Properties ◽  
High Heat ◽  
Melt Blending ◽  
Gas Barrier ◽  
Heat Distortion Temperature ◽  
Hydrolysis Process ◽  
High Production ◽  
High Production Cost

Poly(glycolic acid) (PGA) holds unique properties, including high gas barrier properties, high tensile strength, high resistance to common organic solvents, high heat distortion temperature, high stiffness, as well as fast biodegradability and compostability. Nevertheless, this polymer has not been exploited at a large scale due to its relatively high production cost. As such, the combination of PGA with other bioplastics on one hand could reduce the material final cost and on the other disclose new properties while maintaining its “green” features. With this in mind, in this work, PGA was combined with two of the most widely applied bioplastics, namely poly(l-lactide) (PLLA) and poycaprolactone (PCL), using the melt blending technique, which is an easily scalable method. FE-SEM measurements demonstrated the formation of PGA domains whose dimensions depended on the polymer matrix and which turned out to decrease by diminishing the PGA content in the mixture. Although there was scarce compatibility between the blend components, interestingly, PGA was found to affect both the thermal properties and the degradation behavior of the polymer matrices. In particular, concerning the latter property, the presence of PGA in the blends turned out to accelerate the hydrolysis process, particularly in the case of the PLLA-based systems.

A Short Review on Recent Development of Laccase Immobilization on Different Support Materials

2021 ◽  
Vol 02 (01) ◽  
Author(s):  
Norsyafiqah Amalina Ahmad Jafri ◽  
◽  
Roshanida A. Rahman ◽  
Noorhalieza Ali ◽  
◽  
...  
Keyword(s):  
Large Scale ◽  
Cost Effective ◽  
Short Review ◽  
Industrial Applications ◽  
Innovative Strategies ◽  
Support Materials ◽  
High Production ◽  
Efficient Recovery ◽  
High Production Cost ◽  
Laccase Immobilization

Laccase is a bio catalytic agent and multi-copper enzyme containing oxidases that are potentially great for oxidizing large number of phenolic and non-phenolic compounds. However, drawbacks do arise when laccase use in large scale; low in stability, high production cost, non-reusability, sensitive towards denaturing and poor storage ability of free enzymes. These problems lead to the progress in laccase immobilization in order to facilitate the efficient recovery and re-use of the enzyme, thus enabling cost-effective in continuous processes. Apart from discussing on different methods in laccase immobilization such as entrapment, encapsulation and cross-linking in general, we have reviewed a recent development in laccase immobilization on different supports or carriers binding (natural and synthetic). Future works are recommended to focus on innovative strategies on the modified supports to improve the enzyme immobilization as well as sensible entrapment techniques for industrial applications.

scholarly journals Elucidation of new xylose metabolizing pathway in Pseudomonas gessardii VXlt-16 and its correlation with xylitol production from sugarcane bagasse hydrolysate

2021 ◽  
Author(s):  
Vishal Ahuja ◽  
Sanjeev Mehta ◽  
Ranju Kumari Rathour ◽  
Vaishali Sharma ◽  
Nidhi Rana ◽  
...  
Keyword(s):  
Large Scale ◽  
Xylose Reductase ◽  
Xylose Isomerase ◽  
Operating Conditions ◽  
Raw Material ◽  
Xylitol Production ◽  
Sugarcane Bagasse Hydrolysate ◽  
Rdna Sequencing ◽  
High Production ◽  
High Production Cost

Abstract Scientific interventions have identified lignocellulosic biomass as potential raw material for various industrial processes. However toxic byproducts released during the process result in deterioration of environment to a greater extent. Microbes can utilize these wastes for production of products of commercial value like bio-fuels, protein, organic acids and xylitol. However, high production cost and astringent operating conditions have been the major bottlenecks for its commercial production. In microbes, xylose is metabolized by xylose isomerase (XI) and xylose reductase-xylitol dehydrogenase (XR-XDH) pathways, with later having ability to transform pure xylose as well as xylose rich lignocelluloses. Efforts to find hyper producer isolates for xylitol production resulted in identification of one such isolate Pseudomonas gessardii VXlt-16 (MG770460) by 16s rDNA sequencing. Statistical optimization resulted in 7.28 folds’ increase in xylitol yield with 64.76% xylose bioconversion. Conversion of xylose to xylitol even at large scale suggests the possible application of bacterial isolate for the production of this useful product at industrial scale.

scholarly journals Elucidation of New Xylose Metabolizing Pathway in Pseudomonas Gessardii VXlt-16 and its Correlation with Xylitol Production from Sugarcane Bagasse Hydrolysate

2021 ◽  
Author(s):  
Vishal Ahuja ◽  
Sanjeev Mehta ◽  
Ranju Kumari Rathour ◽  
Vaishali Sharma ◽  
Nidhi Rana ◽  
...  
Keyword(s):  
Large Scale ◽  
Xylose Reductase ◽  
Xylose Isomerase ◽  
Operating Conditions ◽  
Raw Material ◽  
Xylitol Production ◽  
Sugarcane Bagasse Hydrolysate ◽  
Rdna Sequencing ◽  
High Production ◽  
High Production Cost

Abstract Scientific interventions have identified lignocellulosic biomass as potential raw material for various industrial processes. However toxic byproducts released during the process result in deterioration of environment to a greater extent. Microbes can utilize these wastes for production of products of commercial value like bio-fuels, protein, organic acids and xylitol. However, high production cost and astringent operating conditions have been the major bottlenecks for its commercial production. In microbes, xylose is metabolized by xylose isomerase (XI) and xylose reductase-xylitol dehydrogenase (XR-XDH) pathways, with later having ability to transform pure xylose as well as xylose rich lignocelluloses. Efforts to find hyper producer isolates for xylitol production resulted in identification of one such isolate Pseudomonas gessardii VXlt-16 (MG770460) by 16s rDNA sequencing. Statistical optimization resulted in 7.28 folds’ increase in xylitol yield with 64.76% xylose bioconversion. Conversion of xylose to xylitol even at large scale suggests the possible application of bacterial isolate for the production of this useful product at industrial scale.

Gas barrier properties of natural rubber/kaolin composites prepared by melt blending

2010 ◽  
Vol 50 (2) ◽  
pp. 255-259 ◽  
Author(s):  
Yude Zhang ◽  
Qinfu Liu ◽  
Qian Zhang ◽  
Yinping Lu
Keyword(s):  
Natural Rubber ◽  
Barrier Properties ◽  
Melt Blending ◽  
Gas Barrier ◽  
Gas Barrier Properties

scholarly journals Impact of Backbone Amide Substitution at the Meta- and Para-Positions on the Gas Barrier Properties of Polyimide

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2097
Author(s):  
Qian Wen ◽  
Ao Tang ◽  
Chengliang Chen ◽  
Yiwu Liu ◽  
Chunguang Xiao ◽  
...  
Keyword(s):  
Transmission Rate ◽  
Barrier Properties ◽  
Polyimide Film ◽  
Flexible Display ◽  
Gas Barrier ◽  
Positron Annihilation Lifetime ◽  
Barrier Materials ◽  
Oxygen Transmission Rate ◽  
Display Technology ◽  
Gas Barrier Properties

This study designed and synthesised a meta-amide-substituted dianiline monomer (m-DABA) as a stereoisomer of DABA, a previously investigated para-amide-substituted dianiline monomer. This new monomer was polymerised with pyromellitic dianhydride (PMDA) to prepare a polyimide film (m-DABPI) in a process similar to that employed in a previous study. The relationship between the substitution positions on the monomer and the gas barrier properties of the polyimide film was investigated via molecular simulation, wide-angle X-ray diffraction (WXRD), and positron annihilation lifetime spectroscopy (PALS) to gain deeper insights into the gas barrier mechanism. The results showed that compared with the para-substituted DABPI, the m-DABPI exhibited better gas barrier properties, with a water vapour transmission rate (WVTR) and an oxygen transmission rate (OTR) as low as 2.8 g·m−2·d−1 and 3.3 cm3·m−2·d−1, respectively. This was because the meta-linked polyimide molecular chains were more tightly packed, leading to a smaller free volume and lower molecular chain mobility. These properties are not conducive to the permeation of small molecules into the film; thus, the gas barrier properties were improved. The findings have significant implications for the structural design of high-barrier materials and could promote the development of flexible display technology.

scholarly journals Diamine vapor treatment of viscoelastic graphene oxide liquid crystal for gas barrier coating

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seung Eun Choi ◽  
Sung-Soo Kim ◽  
Eunji Choi ◽  
Ji Hoon Kim ◽  
Yunkyu Choi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Liquid Crystal ◽  
Diffusion Length ◽  
Barrier Properties ◽  
Gas Barrier ◽  
Barrier Coating ◽  
Coating Method ◽  
Gas Molecules ◽  
Pet Film ◽  
Vapor Treatment

AbstractA layered graphene oxide/ethylenediamine (GO/EDA) composite film was developed by exposing aqueous GO liquid crystal (GOLC) coating to EDA vapor and its effects on the gas barrier performance of GO film were systematically investigated. When a GO/EDA coating with a thickness of approximately 1 μm was applied to a neat polyethylene terephthalate (PET) film, the resultant film was highly impermeable to gas molecules, particularly reducing the gas permeance up to 99.6% for He and 98.5% for H2 in comparison to the neat PET film. The gas barrier properties can be attributed to the long diffusion length through stacked GO nanosheets. The EDA can crosslink oxygen-containing groups of GO, enhancing the mechanical properties of the GO/EDA coating with hardness and elastic modulus values up to 1.14 and 28.7 GPa, respectively. By the synergistic effect of the viscoelastic properties of GOLC and the volatility of EDA, this coating method can be applied to complex geometries and EDA intercalation can be spontaneously achieved through the scaffold of the GOLC.

A feedback controller for milling chatter vibration control using a new response matrix

2021 ◽  
pp. 107754632098820
Author(s):  
Bashir B Muhammad ◽  
Muhammad Bashir ◽  
Mukhtar F Hamza ◽  
Mustapha Abdulhadi ◽  
Muhammad A Shehu ◽  
...  
Keyword(s):  
Controller Design ◽  
Industrial Process ◽  
Milling Process ◽  
Feedback Controller ◽  
Response Matrix ◽  
Chatter Vibration ◽  
Active Feedback ◽  
High Production ◽  
High Production Cost ◽  
Milling Chatter

A chatter mark is a result of irregular vibration that affects the milling process, which results in poor surface finish, reduced work quality, machine impairment, and high production cost. This work presents an active feedback controller design using a new response matrix to suppress the free vibration in the milling process. The proposed controller considers feed rate, tooth passing frequency, and time-varying dynamic milling force coefficients. A milling experiment verifies the effect of the proposed method. The method provides a reliable way of tackling chatter vibration in an industrial process. The procedure is technically and economically beneficial.

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