“Green” biocomposites based on cellulose diacetate and regenerated cellulose microfibers: Effect of plasticizer content on morphology and mechanical properties (original) (raw)
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Cellulose Acetate Blends - Effect of Plasticizers on Properties and Biodegradability
Journal of Renewable Materials, 2014
Cellulose acetate (CDA) cannot be processed as raw material because it starts to decompose before melting. Triacetin and diacetin were tested to improve CDA processing versus conventional phthalate as environmentally sustainable plasticizers, because of their low toxicity and fast biodegradability. The addition of triacetin and diacetin allowed melt processing of CDA and the results of tensile tests outlined their effect as plasticizers. The values of mechanical properties were compatible with the requirements for applications in rigid packaging. From the results of biodegradation tests it can be concluded that for pure cellulose acetate, complete biodegradation was obtained within 200 days of testing after reinoculation. Incomplete biodegradation was observed for test items with 20% triacetin or with 30% phthalate. After 46 days of incubation, the test samples with 30% plasticizer based on triacetin or triacetin-diacetin were completely biodegraded. These formulations can be selected for the production of compostable blends and/or biocomposites.
ACS Applied Polymer Materials
In this study, we present the development of ecofriendly biocomposites composed of polylactic acid (PLA) and microcrystalline cellulose (MCC), using melt extrusion and compression molding processes. In all the studied samples, the PLA/MCC ratio was always 1:1, whereas the plasticizer triethyl citrate (TEC) was responsible for the improved dispersion of the MCC in PLA. Tensile tests proved that the developed biocomposites containing TEC show improved ductility and crystallinity, as confirmed by the X-ray diffraction (XRD) study. Furthermore, the water vapor and oxygen permeability of the biocomposites were found to decrease as the TEC content increases in the formulation. Nonetheless, migration analyses to a dry food simulant prove that the migration of TEC is slightly above the acceptable limits when biocomposites with 15 wt % TEC were used. Taking this into account, in combination with the ranking of all the developed biocomposites according to their performance through the technique for order of preference by similarity to ideal solution (TOPSIS) analysis, we concluded that the PLA/MCC samples with 10 wt % TEC can be considered the most suitable biocomposites for eco-friendly food packaging applications. These findings place the developed PLA/MCC biocomposites among the strong candidates for biobased food packaging materials able to be produced at a large scale following industrially applicable methods since they are cost-effective and have improved properties compared to the pure biopolymer.
Cellulose and Starch as the Source of Bioplastic
international journal for research in applied science and engineering technology ijraset, 2020
Over last several years, need of the polymers has increased. Polymers are a broad class of materials that can be natural in origin or synthetic. Very small variations in the chemical structure of polymer could lead to large change in their biodegradability. A vast number of biodegradable polymers (example: chitin, starch, polyhydroxyalkanoate, polylactide, polycaprolactone including polypeptides) has been synthesized or is formed in natural environment during the growth cycles of different organism. Microorganisms and enzymes capable of degrading such polymers have been identified. The use of additives like sorbitol, glycerol and poly ethylene glycol will enhance strength and thermal stability of polymers during processing. Already existing biopolymers are facing the issues in meeting market demand, cost of manufacturing, being non recyclable, release of carbon dioxide during manufacturing and release of methane gas during degradation. These issues can be overcome by novel starch and cellulose based bioplastic produced from biomass. Bioplastic will meet the market demand and degrade in the soil at high temperature.
Biodegradation - Engineering and Technology, 2013
Table 1. Classification of natural polymers based on their sources. There are several types of carbohydrates: monosaccharides, disaccharides, oligosaccharides and polysaccharides. The latter ones, of particular interest, are comprised of hundreds or thousands of monosaccharides, commonly glucose, forming linear chains, such as cellulose, or branched chains, as in starch and glycogen. For this chapter, cellulose and its derivatives, starch and chitosan will be presented as natural biodegradable polymers [10]. 2.1.1. Cellulose derivatives Cellulose acetate (CA), universally recognized as the most important organic ester of cellulose because of its extensive applications in fibres, plastics and coatings, is prepared by reacting cellulose with acetic anhydride using acetic acid as a solvent and perchloric acid or sulphuric acid as a catalyst. CA is a carbohydrate composed of β-glucose molecules that are covalently linked through β-1,4-glycosidic bonds, widely found in nature in algae and land plants which has been valued as a functional material. CA comes to meeting the diverse needs of today's society including biodegradability characteristics, its hydrophilic behaviour and biocompatibility [11]. Several applications for cellulose and its derivatives have been shown, for example: in paints, textiles, pharmaceuticals and beauty, fibers, ionic liquids, construction technology and so on [12, 13]. Cellulose esters for coating applications are nearly always used as miscible blends with acrylics, polyesters and other polymers. This is possible because of their ability to form hydrogen bonds through the presence of hydroxyl groups and the carboxyl groups of the ester. An increase in ester molecular weight increases the toughness and melting point but decreases the compatibility and solubility, whereas hardness and density are unaffected. Compatibility, solubility and the maximum non-volatile content all decrease as the ester molecular weight increases. The hydroxyl group content inversely affects the moisture resistance and toughness [11]. Ignácio et al. [14] evaluated the production of cellulosic polymer membranes based on cellulose acetate and thus advanced technology was brougth to be used in membranes for separation Biocomposites: Influence of Matrix Nature and Additives on the Properties and Biodegradation Behaviour
The Role of Biopolymers in Obtaining Environmentally Friendly Materials
Composites from Renewable and Sustainable Materials, 2016
Polymeric materials have had a boom in the global industry over the past two decades, because of its adaptability, durability, and price so much so that now we cannot imagine a product that does not contain it. However, many synthetic polymers that have been developed are mainly derived from petroleum and coal as raw material, which make them incompatible with the environment, since they cannot be included in what is a natural recycling system. Aware of the environmental impacts that produce synthetic polymers, a solution could be the mixtures with different types and sources of biological materials, called biopolymers, such as starch, cellulose, chitosan, zein, gelatin among others and that gradually replace synthetic polymers to address and resolve these problems. The development of new applications, such as composite materials by incorporation of alternative materials, found in nature that has similar properties to oilbased polymers, but its main feature is its biodegradability and offering competitive to current material costs. In this sense, various investigations are aimed at decreasing the amounts of plastic waste and to manufacture products with less aggressive environment since the synthetic plastics are difficult to recycle and can remain in nature for over a century.
Environmental Science and Pollution Research, 2016
The plastic materials used for packaging are increasing leading to a considerable amount of undegradable solid wastes. This work deals with the reduction of conventional plastics waste and the natural resources preservation by using cellulosic polymers from renewable resources (alfa and luffa). Plasticized starch films syntheses were achieved at a laboratory scale. These natural films showed some very attractive mechanical properties at relatively low plasticizers levels (12 to 17 % by weight). Furthermore, mixtures including polylactic acid polymer (PLA) and cellulose fibers extracted from alfa and luffa were investigated by melt extrusion technique. When used at a rate of 10 %, these fibers improved the mixture mechanical properties. Both developed materials were biodegradable, but the plasticized starch exhibited a faster biodegradation kinetic compared to the PLA/cellulose fibers. These new materials would contribute to a sustainable development and a waste reduction.