scholarly journals Potential of Cellulose Microfibers for PHA and PLA Biopolymers Reinforcement

Molecules ◽  
2020 ◽  
Vol 25 (20) ◽  
pp. 4653
Author(s):  
Gonzalo Mármol ◽  
Christian Gauss ◽  
Raul Fangueiro
Keyword(s):  
Lignin Content ◽  
Barrier Properties ◽  
Production Costs ◽  
Recycled Paper ◽  
High Fiber ◽  
Kraft Paper ◽  
Layer Composite ◽  
Mechanical And Physical Properties ◽  
Cellulose Microfibers ◽  
Current Production

Cellulose nanocrystals (CNC) have attracted the attention of many engineering fields and offered excellent mechanical and physical properties as polymer reinforcement. However, their application in composite products with high material demand is complex due to the current production costs. This work explores the use of cellulose microfibers (MF) obtained by a straightforward water dispersion of kraft paper to reinforce polyhydroxyalkanoate (PHA) and polylactic acid (PLA) films. To assess the influence of this type of filler material on the properties of biopolymers, films were cast and reinforced at different scales, with both CNC and MF separately, to compare their effectiveness. Regarding mechanical properties, CNC has a better reinforcing effect on the tensile strength of PLA samples, though up to 20 wt.% of MF may also lead to stronger PLA films. Moreover, PHA films reinforced with MF are 23% stronger than neat PHA samples. This gain in strength is accompanied by an increment of the stiffness of the material. Additionally, the addition of MF leads to an increase in the crystallinity of PHA that can be controlled by heat treatment followed by quenching. This change in the crystallinity of PHA affects the hygroscopicity of PHA samples, allowing the modification of the water barrier properties according to the required features. The addition of MF to both types of polymers also increases the surface roughness of the films, which may contribute to obtaining better interlaminar bonding in multi-layer composite applications. Due to the partial lignin content in MF from kraft paper, samples reinforced with MF present a UV blocking effect. Therefore, MF from kraft paper may be explored as a way to introduce high fiber concentrations (up to 20 wt.%) from other sources of recycled paper into biocomposite manufacturing with economic and technical benefits.

scholarly journals Pupation Substrate Type and Volume Affect Pupation, Quality Parameters and Production Costs of a Reproductive Colony of Ceratitis capitata (Diptera: Tephritidae) VIENNA 8 Genetic Sexing Strain

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 337
Author(s):  
Carlos Pascacio-Villafán ◽  
Luis Quintero-Fong ◽  
Larissa Guillén ◽  
José Pedro Rivera-Ciprian ◽  
Reynaldo Aguilar ◽  
...  
Keyword(s):  
Wheat Bran ◽  
Ceratitis Capitata ◽  
Mass Rearing ◽  
Physicochemical Characteristics ◽  
Production Costs ◽  
Cellulose I ◽  
Coconut Fiber ◽  
Genetic Sexing ◽  
Recycled Paper ◽  
Genetic Sexing Strain

Adequate pupation substrates and substrate volume are critical factors in the mass-rearing of insects for Sterile Insect Technique (SIT) applications. To identify an ideal pupation substrate for a reproductive colony of Ceratitis capitata (Wiedemann) VIENNA 8 genetic sexing strain, we first examined pupation in cellulose from recycled paper (cellulose I), sawdust, fine wheat bran, vermiculite and coconut fiber using a volume of 2.5–12.5 mL of substrate for each 5 mL volume of fly larvae. We found a positive relationship between substrate volume and pupation, with cellulose I generating the highest proportions of pupation and coconut fiber the lowest. Higher proportions of female flies (white pupae) pupated in sawdust. The proportion of female fliers increased as substrate volume rose in sawdust and coconut fiber, whereas it decreased in vermiculite and cellulose. In a second experiment, we tested three types of cellulose differing in physicochemical characteristics (celluloses I, II and III), sawdust, and fine wheat bran using a substrate:larvae ratio of 1:1. The three types of cellulose produced the highest pupation levels. The highest proportions of female fliers were observed in sawdust, and cellulose types III and II. Cellulose III and sawdust at relatively low volumes were more cost-effective to produce one million pupae than other substrates, including fine wheat bran used in a mass-rearing facility in Mexico.

Formation and Electrochemical Properties of the Hydrophobic Composite Coatings on Aluminum Alloy

2018 ◽  
Vol 386 ◽  
pp. 315-320
Author(s):  
Vladimir S. Egorkin ◽  
Igor E. Vyaliy ◽  
Nikolay S. Sviridov ◽  
Alexander N. Minaev ◽  
Sergey L. Sinebryukhov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Composite Coatings ◽  
Morphological Structure ◽  
Barrier Properties ◽  
Base Layer ◽  
Layer Composite ◽  
Electrolytic Oxidation ◽  
Different Types ◽  
Plasma Electrolytic ◽  
High Level

Plasma electrolytic oxidation (PEO) of 5754 aluminum alloy in a tartrate electrolyte was carried out to form a base layer. Composite fluoropolymer coatings were obtained on the base layers in two ways allowing the formation of two different types of morphological structure: a continuous polymer film and a multimodal islet relief. The resulted coatings exhibit substantially different wettability along with high level of barrier properties.

scholarly journals Gıda Endüstrisinde Kitosan Filmlerin Önemi

2013 ◽  
Vol 1 (2) ◽  
pp. 79 ◽  
Author(s):  
Filiz Uçan ◽  
Hatice Aysun Mercimek
Keyword(s):  
Fruits And Vegetables ◽  
Moisture Transfer ◽  
Barrier Properties ◽  
Edible Films ◽  
Production Costs ◽  
Film Forming ◽  
Materials Used ◽  
Bacteria And Fungi ◽  
Simple Technology ◽  
Storage Times

Requirement simple technology, low production costs, lack of polluting effects and reliability in terms of health of it is the most important advantages of edible films. Chitosan that extend the shelf life of food and increase the economic efficiency of packaging materials is one of the new materials used for edible films. Chitosan was obtained by deacetylation of chitin which is the most commonly occurred polymer after cellulose in nature, in shells of arthropods such as crab, shrimp, lobster and in cell walls of some bacteria and fungi. Chitosan has the important bioactive properties such as hemostatic, bacteriostatic, fungistatic, spermicidal, anticarcinogenic, anticholesteremic, antacids, antiulcer, wound and bone healing accelerator and stimulating the immune system. As well as these features, the film forming and barrier properties of its, chitosan is made the ideal material for edible films and coatings in antimicrobial characters. Especially, in the protection of qualities and the improving storage times of fruits and vegetables, have been revealed the potential use of chitosan. The coating food with chitosan films reduces the oxygen partial pressure in the package, maintains temperature with moisture transfer between food and its environment, declines dehydration, delays enzymatic browning in fruits and controls respiration. In addition to, chitosan are also used on issues such as the increasing the natural flavour, setting texture, increasing of the emulsifying effect, stabilization of color and deacidification.

scholarly journals Comparison of the Functional Barrier Properties of Chitosan Acetate Films with Conventionally Applied Polymers

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3491
Author(s):  
Andrea Walzl ◽  
Samir Kopacic ◽  
Wolfgang Bauer ◽  
Erich Leitner
Keyword(s):  
Polymer Films ◽  
Food Packaging ◽  
Barrier Properties ◽  
Good Alternative ◽  
Recycled Paper ◽  
Plastic Bags ◽  
Plastic Materials ◽  
Oil Hydrocarbons ◽  
Migration Experiment ◽  
Materials Used

The current demand to cut back on the use of plastic materials has brought a major boost to the search for bio-based alternatives. Not only are plastic bags and primary food packaging under scrutiny here, but also those materials used as functional barriers to reduce, for example, the migration of mineral oil hydrocarbons (MOH) from recycled paper and board packaging. Most of the barriers now in use are synthetic, often have only moderate barrier functionalities and in addition reduce the environmentally-friendly character of cellulose-based materials. Against this background, bio-based polymers have been evaluated in terms of their functional barrier properties. Chitosan was found to be among the best performers in these materials. In this study, the behavior of a lab-made chitosan acetate film was compared with conventionally produced polymer films. The two-sided migration experiment described recently was used to determine the barrier properties of the tested materials. This not only allowed to test the intrinsic migration of the films and the permeation through them, but also to simulate real packaging situations by using a recycled paper as donor for MOH. The migrated fractions were determined using gas-chromatography-based techniques. While the conventionally produced polymer films showed only moderate barrier function, excellent results were seen for the biopolymer. It reduced the migration from the recycled paper to not detectable, singling it out as a good alternative to conventional materials.

Toughening, Thermal Stability, Flame Retardancy, and Scratch–Wear Resistance of Polymer–Clay Nanocomposites

2007 ◽  
Vol 60 (7) ◽  
pp. 496 ◽  
Author(s):  
Aravind Dasari ◽  
Szu-Hui Lim ◽  
Zhong-Zhen Yu ◽  
Yiu-Wing Mai
Keyword(s):  
Thermal Stability ◽  
Wear Resistance ◽  
Flame Retardancy ◽  
Interfacial Area ◽  
Barrier Properties ◽  
Clay Nanocomposites ◽  
Positive Effects ◽  
Large Numbers ◽  
Mechanical And Physical Properties ◽  
Wear Response

Addition of a small percent of clay to polymers improves their stiffness, strength, dimensional stability, and thermal, optical, and barrier properties. Improvements are often attributed to the availability of large numbers of clay nanolayers with tremendous interfacial area. Despite the positive effects from the addition of clay, there are unresolved issues, such as embrittlement, thermal stability, flame retardancy, scratch–wear response of the resultant nanocomposites, and/or achieving a balance between different mechanical and physical properties. In this review, we discuss these issues and the approaches that have been adopted in the expectation of resolving and understanding them, with particular emphasis on our recent and current research.

The Influence of a Non-Occlusive Bi-Layer Composite Membrane on Skin Barrier Properties

2008 ◽  
Vol 21 (1) ◽  
pp. 50-55 ◽  
Author(s):  
V. Brazzelli ◽  
E. Berardesca ◽  
C. Rona ◽  
G. Borroni
Keyword(s):  
Composite Membrane ◽  
Skin Barrier ◽  
Barrier Properties ◽  
Layer Composite

Modelling of Polydomain Smart Materials

1994 ◽  
Vol 360 ◽  
Author(s):  
Yongsik Yu ◽  
Alexander Roytburd
Keyword(s):  
Physical Properties ◽  
Electric Fields ◽  
Smart Materials ◽  
Practical Importance ◽  
Thermodynamic Theory ◽  
Domain Formation ◽  
Domain Structures ◽  
Layer Composite ◽  
Mechanical And Physical Properties

AbstractPolydomain materials with periodic (modulated) domain structures are of potential practical importance since they can possess unique and desirable mechanical and physical properties. A twin related domain formation can be a result of constrained structural, ferroelectric or ferromagnetic transformations. The thermodynamic theory on the deformation of layer composites containing a polydomain (polytwin) ferroelectric component is analyzed. The deformation of the layer composite under different directional electric fields and constraints is calculated.

Application of modified cellulose nanofibrils as coating suspension on recycled paper using size press

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hakan Fidan ◽  
Ayhan Tozluoğlu ◽  
Ahmet Tutuş ◽  
Bayram Poyraz ◽  
Recai Arslan ◽  
...  
Keyword(s):  
Cellulose Nanofibrils ◽  
Barrier Properties ◽  
Coating Material ◽  
Compression Tests ◽  
Recycled Paper ◽  
Paper Properties ◽  
Lower Viscosity ◽  
Coating Suspension ◽  
End Use ◽  
Recycled Fibers

Abstract Cellulose based nanomaterials have the great potential to be applied to paper as bulk additive or coating material to improve overall final properties, especially in secondary fiber. In the present work, the effect of applying different kinds of cellulose nanofibrils (CNF) to papers obtained from recycled fibers using size press on physical, mechanical and barrier properties was investigated and compared with the sole use of starch as coating material. The coating process of CNF was carried out by the addition of size press grade starch to coating suspension. As a cellulose source, wheat straw was evaluated and CNF was obtained through oxidative and enzymatic pretreatments. Results indicate that starch/CNF suspension improves the overall paper properties. As a result of the deposition of coating suspension contains of 4 % wt. periodate-oxidized CNF onto paper surface, tensile and burst indices of papersheets increased as 52.2 % and 194.4 %. Significant decreases were observed in air permeability as 69.8 %. Compression tests also have been conducted to evaluate papersheets end-use properties. In comparison to the other pretreated CNF, due to is lower viscosity, applying periodate-oxidized CNF as size press significantly increased the mechanical properties of the papers fabricated from the recycled pulps.

Strength Loss in Recycled Fibers and Methods of Restoration

1992 ◽  
Vol 266 ◽  
Author(s):  
James L. Minor ◽  
Rajai H. Atalla
Keyword(s):  
Gas Phase ◽  
Lignin Content ◽  
Strength Loss ◽  
Pulp Fibers ◽  
Recycling Process ◽  
Recycled Paper ◽  
Chemical Pulps ◽  
Mechanical Pulps ◽  
Recycled Fibers ◽  
High Lignin Content

AbstractThe reduced interfiber bonding capability and reduced conformability of recycled fibers compared to virgin wood pulp fibers is caused by the drying phase of the first papermaking cycle. Changes in the fiber result in stiffness. This effect is more pronounced in chemical pulps than in high lignin content mechanical pulps. This chapter describes methods for restoring some or all the interfiber bonding. In an attempt to develop a “dry” newspaper recycling process, the water-intensive repulping and paper-forming steps were replaced with dry-fiberizing, air-forming, gas-phase ozone and ammonia treatments, and pressdrying. The tensile strength of the dry-recycled paper approached that of the original newsprint.

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