Production Of Biodegradable Plastics Research Articles

Chemical Recycling of PET in the Presence of the Bio-Based Polymers, PLA, PHB and PEF: A Review

The great increase in the production and consumption of plastics has resulted in large amounts of plastic wastes, creating a serious problem in terms of their environmentally friendly disposal. The need for the production of more environmentally friendly polymers gave birth to the production of biodegradable, and more recently, biobased polymers, used in the production of biodegradable or biobased plastics. Although the percentage of currently produced bioplastics is rather small, almost 1% compared to petrochemical-based plastics, inevitably is going to significantly increase in the near future due to strict legislation recently posed by the European Union and other countries’ Governments. Thus, recycling strategies that have been developed could be disturbed and the economic balance of this sector could be destabilized. In the present review, the recycling of the polymer mainly used in food plastic packaging, i.e., poly(ethylene terephthalate), PET is examined together with its counterparts from the biobased polymers, i.e., poly(lactic acid), PLA (already replacing PET in several applications), poly(3-hydroxybutyrate), PHB and poly(ethylene furanoate), PEF. Methods for the chemical recycling of these materials together with the chemical products obtained are critically reviewed. Specifically, hydrolysis, alcoholysis and glycolysis. Hydrolysis (i.e., the reaction with water) under different environments (alkaline, acidic, neutral), experimental conditions and catalysts results directly in the production of the corresponding monomers, which however, should be separated in order to be re-used for the re-production of the respective polymer. Reaction conditions need to be optimized with a view to depolymerize only a specific polymer, while the others remain intact. Alcoholysis (i.e., the reaction with some alcohol, methanol or ethanol) results in methyl or ethyl esters or diesters that again could be used for the re-production of the specific polymer or as a source for producing other materials. Glycolysis (reaction with some glycol, such as ethylene, or diethylene glycol) is much studied for PET, whereas less studied for the biopolymers and seems to be a very promising technique. Oligomers having two terminal hydroxyl groups are produced that can be further utilized as starting materials for other value-added products, such as unsaturated polyester resins, methacrylated crosslinked resins, biodegradable polyurethanes, etc. These diols derived from both PET and the bio-based polymers can be used simultaneously without the need for an additional separation step, in the synthesis of final products incorporating biodegradable units in their chemical structure.

General Aspects of Biodegradable Biopolymers and the Polyhydroxyalkanoates' Family

Background: Plastic polymers are ubiquitous, and life without them is practically impossible. Despite the advantages provided by the material, conventional plastics are also harmful to the environment and human health. Therefore, the search for alternatives, such as polyhydroxyalkanoates (PHAs), a family of biodegradable thermoplastic polyesters naturally produced by PHA-accumulating bacteria, such as Pseudomonas spp. and Ralstonia eutropha, through fermentative processes, is of paramount importance. Objectives: In the present work, the objective of the researchers was to develop a revisional study regarding biodegradable biopolymers and PHAs’ importance and benefits for society and the environment. Methods: In this review, articles published since the year 2000 related to the different aspects of biodegradable plastics and PHAs, were accurately analyzed and reviewed. The subjects covered ranged from conventional plastics and the problems related to their large-scale production and the importance of biodegradable plastics, as well as PHAs, their positive aspects, and the feasibility of their use as an alternative to replace conventional plastics. Those subjects were extensively reviewed and concisely discussed. Results and Conclusions: The present study demonstrated the importance of biodegradable plastics and PHAs’ family, its different application possibilities, and its viability as an alternative to replace conventional plastics, since it can mimic their characteristics efficiently, with the advantage of being biodegradable and produced from renewable sources.

Structural assessment of the bioplastic (poly-3-hydroxybutyrate) produced by Bacillus flexus Azu-A2 through cheese whey valorization

The demand for the production of biodegradable plastics has significantly increased. Bioplastics have become an essential alternative to the threats of the daily consumable plastics, sourced from fossil fuels, to the environment. Polyhydroxyalkonates (PHAs) are a ubiquitous group of bioderived and biodegradable plastics, however their production is limited by the costs associated mainly with the carbon sources. Herein, this study aims to reduce the PHAs production cost by using a by-product from the dairy industry, i.e., cheese whey (CW), as a sole carbon source. The developed process recruits an aquatic isolate, Bacillus flexus Azu-A2, and is optimized via studying various parameters using the shaking flasks technique. The results showed that the maximum PHA production (0.95 g L-1) and PHA content (20.96%, w/w), were obtained after incubation period 72 h at 45 °C, 100 rpm agitation rate, 50% CWS concentration, pH 8.5, and 1.0 g L-1 ammonium chloride. Physiochemically, Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectroscopy (GC–MS), nuclear magnetic resonance (NMR), and energy-dispersive X-ray (EDX) techniques, emphasized the type of the extracted PHA as polyhydroxybutyrate (PHB). The thermal properties of PHB were measured using differential scanning calorimetry (DSC), recording melting transition temperature (Tm) at 170.96 °C. Furthermore, a scanning electron microscope (SEM) visualized a homogenous microporous structure for the thin PHB biofilm. In essence, this study highlights the ability of Bacillus flexus Azu-A2 to produce a good yield of highly purified PHB at reduced production cost from dairy CW. Consequently, the current study paves the way for an improved whey management strategy.

Initial Properties Identification of Refined- and Semi Refined-Carrageenans as Raw Materials for Biodegradable Plastic Production

Powdered refined- and semi-refined carrageenans (RC and SRC) have been characterized as alternative raw materials for industrial bioplastic production. Several basic parameters, i.e., the melting temperature, crystallinity, chemical structure (FTIR), and tensile properties, were observed. The melting temperature of RC was slightly higher than that of SRC, i.e., 176 °C and 172 °C, respectively. These temperatures were corresponded to their crystallinity degree (performed by X-ray diffraction). Nonetheless, the SRC demonstrated an overall higher thermal stability during heating. RC produced a clear transparent film. Meanwhile, SRC was yellowish and less transparent. The overall mechanical properties showed that RC produced more flexible film than SRC. However, both materials showed relatively equal tensile strength. In general, RC and SRC could be potentially used for biodegradable film production with different applications. RC was suitable for a flexible and clear plastic film, whereas SRC was suitable for rigid plastic film applications.

Expanding Policy for Biodegradable Plastic Products and Market Dynamics of Bio-Based Plastics: Challenges and Opportunities

Bio-plastics are rapidly growing in popularity, and many new techniques and approaches are emerging as a result of intensive research and development (R&D) activities. Many industries worldwide are installing their new production capability. Bio-plastics have attracted political leaders’ interest, especially in light of the evolving bio-economic orientation, through their use of renewable resources and their effects on sustainable growth. Related market determinants are defined, classified, and used as a base for their own estimates. The evolution of global production capacity is modeled annually for the timeframe up to 2030 by applying a system dynamics strategy. For a long-term forecast to catch the inherent volatility, various scenarios are identified and added to the model to represent different trends in the price of gross domestic product (GDP), oil, and bioplastic feedstock. Thus, our findings show the sensitivity in the macro-economic climate of the bioplastics sector. The simulations are completed by a debate on the regulatory environment and its future effect on industry development at the European level. The findings show considerable potential for development but are vulnerable to political and economic impacts.

Inactivation of phosphate regulator (SphU) in cyanobacterium Synechocystis sp. 6803 directly induced acetyl phosphate pathway leading to enhanced PHB level under nitrogen-sufficient condition

Poly-β-hydroxybutyrate (PHB) is a biodegradable and biocompatible polymer that has potential in the fields of environmental, agricultural, and biomedical sciences. Cyanobacteria are considered an excellent source of PHB by bioconversion of CO2. This study aimed to prolong PHB production under nitrogen-sufficient condition in the model cyanobacterium Synechocystis sp. PCC 6803. Interestingly, the lack of phosphate regulator (SphU) enabled the mutant strain (ΔSphU) to have the ability to accumulate phosphate with higher expression of Pho regulon. When strain ΔSphU was cultured in nitrogen complete medium for 14 days, the PHB granules were more extensively accumulated in the ΔSphU strain than in the wild type. Photosynthesis activity slightly increased in ΔSphU strain, with no significant difference in chlorophyll a content between wild-type and ΔSphU strain in nitrogen-containing medium, indicating that the higher PHB content (14.57% (w/w) cell dry weight) was not influent of chlorosis. The RT-qPCR analysis revealed that genes involved in PHB biosynthesis and acetyl phosphate pathway were more upregulated in ΔSphU strain. Moreover, the level of acetate production in ΔSphU cells was higher than that in the wild type, suggesting that the deletion of the phosphate regulator could directly induce PHB metabolism by activation of the acetyl phosphate pathway. This research provides better understanding of PHB production regulation in cyanobacteria which are a promising hosts for industrial production of biodegradable plastics.

Metabolomic Study of Heterotrophically Grown Chlorella sp. Isolated from Wastewater in Northern Sweden.

There are numerous strains of Chlorella with a corresponding variety of metabolic pathways. A strain we previously isolated from wastewater in northern Sweden can grow heterotrophically as well as autotrophically in light and has higher lipid contents under heterotrophic growth conditions. The aims of the present study were to characterize metabolic changes associated with the higher lipid contents in order to enhance our understanding of lipid production in microalgae and potentially identify new compounds with utility in sustainable development. Inter alia, the amino acids glutamine and lysine were 7-fold more abundant under heterotrophic conditions, the key metabolic intermediate alpha-ketoglutarate was more abundant under heterotrophic conditions with glucose, and maltose was more abundant under heterotrophic conditions with glycerol than under autotrophic conditions. The metabolite 3-hydroxy-butyric acid, the direct precursor of the biodegradable plastic PHB (poly-3-hydroxy-butyric acid), was also more abundant under heterotrophic conditions. Our metabolomic analysis has provided new insights into the alga’s lipid production pathways and identified metabolites with potential use in sustainable development, such as the production of renewable, biodegradable plastics, cosmetics, and nutraceuticals, with reduced pollution and improvements in both ecological and human health.

Superior thermal stability and fast crystallization behavior of a novel, biodegradable \u03b1-methylated bacterial polyester

Given their ubiquity in modern society, the development of biodegradable and renewably sourced plastics is essential for the creation of an environmentally sustainable society. One of the drawbacks for currently available biodegradable plastics such as poly(l-lactic acid) (PLLA) and polyhydroxyalkanoates (PHAs) is that it is difficult to simultaneously achieve mechanical flexibility and certain crystallization behavior in these materials, which limits their use as replacements for established petroleum-based plastics such as isotactic polypropylene (iPP). Here, we report the synthesis and characterization of a new biodegradable plastic, poly(3-hydroxy-2-methylbutyrate) [P(3H2MB)], which is a member of the bacterial PHA family whose members include an α-methylated monomer unit. Biosynthesis of P(3H2MB) was achieved using recombinant Escherichiacoli expressing an engineered pathway. Biosynthesized P(3H2MB) exhibited the highest melting temperature (197 °C) among the biosynthesized PHAs and improved thermal resistance. It also exhibited improved crystallization behavior and mechanical flexibility nearly equal to those of iPP. The primary nucleation rate of P(3H2MB) was faster than that of P(3HB), and the spherulite morphology of P(3H2MB) was much finer than that of P(3HB). This crystal morphology may result in more rapid crystallization behavior, increased transparency, and enhanced mechanical properties. The superior physical properties of P(3H2MB) have the potential to open new avenues for the production of high-performance biodegradable plastics for replacing petroleum-based bulk commodity plastics.

Potential of macroalgae-based biorefinery for lactic acid production from exergy aspect

The increasing production of plastics has raised concerns over the depletion of fossil fuels. In addition, the environmental issues associated with the improper management of plastic waste are increasingly alarming. Therefore, there is a sharp rise of researches conducted on one of the most promising biopolymers for the production of biodegradable plastics, which is known as polylactic acid (PLA). Subsequently, this has led to an increased interest in the production of its monomer, lactic acid (LA). However, the high production cost of LA has been limiting its large-scale manufacturing. The utilization of expensive raw materials and complicated downstream processes have led to the high overall production cost of LA. This review explores the potential of 3G feedstock, specifically macroalgae biomass, as a substrate for LA production. Then, the recent technological advancements for LA production and the challenges currently faced in the LA industry are addressed. Lastly, the sustainability aspect of macroalgae biomass is evaluated economically and environmentally by utilizing engineering tools such as life cycle assessment and exergy analysis, which represent the highlights of this review paper.

Production of biodegradable plastics using aking rice starch and chitosan from crab shells as a substitute for conventional plastic

The aim of this research is to make biodegradable plastics using starch and chitosan from crab shells as a substitute for conventional plastic. Biodegradable plastic synthesis can utilize organic materials such as crab shell waste and Aking rice as the basic ingredients. Crab shells are used as basic ingredients because they contain chitosan which has several beneficial properties namely biocompability, biodegradability, hydrophilicity and antibacterial. Meanwhile, aking rice waste which is a household waste can also be used as a biodegradable plastic base material because it contains starch consisting of two types of polymers namely amylose and amylopectin which can form a thin layer. In the manufacture of bioplastics, a transparent and strong enough sample was obtained, namely 1 g of chitosan, 3% glycerol and bioplastic which had sufficient flexibility but had an uneven surface, namely 2 gr chitosan, 5% glycerol samples. Plastics with the highest percentage of biodegradation, 33.3%, were found in samples with 1 g of chitosan, 3% glycerol, while the lowest percentage of biodegradation was 2% which was obtained in samples with 2 gr chitosan, 5% glycerol.

Conventional Plastics' Harmful Effects and Biological and Molecular Strategies for Biodegradable Plastics' Production

Background: Plastic materials are ubiquitous and, despite the great benefits and advantages that the materials provide to human beings and society, their harmful effects are remarkable. Plastics’ ingestion is harmful and can occur through microplastics and their by-products (BPA and DEHP). It can trigger health problems. Also, the material decomposition time is significant and consequently, plastic waste accumulates in the environment, posing a major problem to fauna and flora. Objectives: The aim of this study is to develop a review of conventional plastics’ negative aspect in human and environmental life, as well as to study the existing biological and molecular strategies for the production of biodegradable plastics, making a comparison of their advantages over conventional plastics, in favor of socio-environmental welfare. Methods: In this review, articles published in the last 20 years related to different aspects of conventional plastics and biodegradable plastics were accurately analyzed and reviewed. The subjects addressed ranged from conventional plastics and the problems related to their large-scale production, as well as biodegradable plastics, their advantages and the most recent advances in the development of production methods and improvement of these biopolymers were extensively reviewed and discussed concisely. Results: The present study demonstrated that, among the biopolymers discussed, thermoplastic starch (TPS) is the most promising one due to its low cost, being one of the best materials to provide a viable alternative in the search for biodegradable plastics. Polylactic acid (PLA) presents the greatest potential for future medical applications due to its unique physicochemical properties and the possibility of being used in 3D printing techniques.Polyhydroxyalkanoates (PHAs) have the greatest commercial potential in replacing fossil fuel-based plastics because of their similar properties to conventional plastics and because they are synthesized by microorganisms from renewable carbon sources. Conclusions: This study demonstrated the various harmful effects that the large-scale use and improper disposal of conventional plastic materials generated to the environment and human health, and proposed an alternative to this problem, the biodegradable plastics. Although this study presented three promising biodegradable plastics (TPS, PLA and PHAs), as well as described their production methods, there are currently no viable biodegradable plastic polymers that can be used for the total replacement of conventional plastics, especially from an economic perspective. However, in the future, modifications in the production methods and chemical structures of these polymers will allow the replacement of conventional plastics by biodegradable plastics, as well as a more extensive application of these biopolymers.

Physical and Mechanical Properties of Biodegradable Plastic Produced From Jackfruit (Artocarpus heterophyllus) Seed and Sago Starch Blend

Objective:: Jackfruit (Artocarpus heterophyllus) is a tropical fruit that has high amylose content in its seeds similar to sago starch. Thus, jackfruit seeds and sago are suitable raw materials for the production of biodegradable plastic (BGP). The objective of this research is to investigate the physical and mechanical properties of BGP produced from the blend of jackfruit seed and sago starch. Methods:: The BGP was prepared by mixing different ratios of the jackfruit seed flour to the sago flour in distilled water with the addition of 0.1 M hydrochloric acid (HCl). The mixture was stirred and heated at 80oC and later mixed with glycerol. The mixture was neutralized with 0.1 M sodium hydroxide (NaOH) and was cast by using the casting plate technique. Results:: The results showed that the optimum tensile strength was obtained at 2.06 MPa. at the blend ratio of 7:3. The maximum absorption rate of water ranged from 32 % to 34 % occurred at the blend ratio of 1:9 while the lowest absorption rate ranged from 21% to 26% occurred at the blend ratio of 5:5. The degradability of BGP was indicated by decreasing the FT-IR spectra peaks intensity and broadening of the bandwidth due to the degradation of starch in the BGP. Conclusion:: The blend ratio of 10:0 showed the highest degradability rate. Conclusively, that the physical and mechanical properties are affected by the blend ratios.

Oxidation of 5-Hydroxymethylfurfural on Supported Ag, Au, Pd and Bimetallic Pd-Au Catalysts: Effect of the Support

Oxidation of 5-hydroxymethylfurfural (HMF), a major feedstock derived from waste/fresh biomass, into 2,5-furandicarboxylic acid (FDCA) is an important transformation for the production of biodegradable plastics. Herein, we investigated the effect of the support (unmodified and modified titania, commercial alumina, and untreated and treated Sibunit carbon) of mono- and bimetallic catalysts based on noble metals (Ag, Au, Pd) on selective HMF oxidation with molecular oxygen to FDCA under mild and basic reaction conditions. The higher selectivity to FDCA was obtained when metals were supported on Sibunit carbon (Cp). The order of noble metal in terms of catalyst selectivity was: Ag < Au < Pd < PdAu. Finally, FDCA production on the most efficient PdAu NPs catalysts supported on Sibunit depended on the treatment applied to this carbon support in the order: PdAu/Cp < PdAu/Cp-HNO3 < PdAu/Cp-NH4OH. These bimetallic catalysts were characterized by nitrogen adsorption-desorption, inductively coupled plasma atomic emission spectroscopy, high resolution transmission electron microscopy, energy dispersive spectroscopy, X-ray diffraction, Hammet indicator method and X-ray photoelectron spectroscopy. The functionalization of Sibunit surface by HNO3 and NH4OH led to a change in the contribution of the active states of Pd and Au due to promotion effect of N-doping and, as a consequence, to higher FDCA production. HMF oxidation catalyzed by bimetallic catalysts is a structure sensitive reaction.

Production of biodegradable plastics using starch and waste fruit peels

Plastic pollution is the accumulation of plastic in the earth’s environment that effects the wildlife, wild habitat and humans. It is inexpensive and takes many years for degradation and resistance to natural processes. Bio plastics are plastics derived from renewable biomass sources such as vegetable fats, oils, corn starch, rice straw, woodchips, food waste and Agricultural bio product. In olden studies, many materials such as woodchip`s, food waste, Agricultural waste, starch, Petro-based polymers, cellulose, nitrocellulose etc., have been used for the production of bio-plastic. In this study, two types of bananas (red and green banana) peels, rice starch, corn starch, potato starch and commercial starch were used in different proportions for the production of bio plastic. After production, its basic properties such as solubility and elongation were analysed. Based on all the testing that was carried out, the bio degradable plastic from the banana peel was found to be the best one compared to other types of bioplastcic.

Biodegradable plastics: Green hope or greenwashing?

The universality of plastic has an inescapable responsibility for the large-scale production of plastic wastes. Fossil-based plastics, which account for the majority of the market, are dazzling, and the global environmental pollution caused by them is also becoming more and more complicated. In addition to controlling the total amount at the source, people have also actively sought some emerging materials to replace existing conventional plastics so that they can be handled better and easier at the end. Biodegradable plastics (BPs) can theoretically shorten the life cycle of plastics and reduce environmental stress. However, in the natural environment, many factors are uncontrollable, and whether BPs can alleviate white pollution needs further certification. Due to the wide and complex physical and chemical conditions encountered in natural ecosystems, great care must be taken in trying to define this term. The current standards and test methods are insufficient to predict the biodegradability of BPs in the natural environment. Additionally, the existing standards and test methods for biodegradability of water environment do not involve toxicity tests, nor do they consider the potentially adverse ecological effects of BPs or micro BPs particles that may be produced by crushing. Therefore, this article mainly discusses whether BPs are green hope or greenwashing: 1) Degradability in the environment; 2) Impact of existing waste management; and 3) Recycling Impact of resources and impact on global carbon sequestration. Successfully solving these knowledge gaps is the key requirement of the new standard for the production of BPs.

Hemp in Veterinary Medicine: From Feed to Drug.

Hemp (Cannabis sativa) is an angiosperm plant belonging to the Cannabaceae family. Its cultivation dates back to centuries. It has always been cultivated due to the possibility of exploiting almost all the parts of the plant: paper, fabrics, ropes, bio-compounds with excellent insulating capacity, fuel, biodegradable plastic, antibacterial detergents, and food products, such as flour, oils, seeds, herbal teas, and beer, are indeed obtained from hemp. Hemp flowers have also always been used for their curative effects, as well as for recreational purposes due to their psychotropic effects. Cannabis contains almost 500 chemical compounds, such as phytocannabinoids, terpenes, flavonoids, amino acids, fatty acids, vitamins, and macro-, and micro-elements, among others. When utilized as a food source, hemp shows excellent nutritional and health-promoting (nutraceutical) properties, mainly due to the high content in polyunsaturated fatty acids (especially those belonging to the ω-3 series), as well as in phenolic compounds, which seem effective in the prevention of common diseases such as gastrointestinal disorders, neurodegenerative diseases, cancer, and others. Moreover, hemp oil and other oils (i.e., olive oil and medium-chain triglyceride–MCT–oil) enriched in CBD, as well as extracts from hemp dried flowers (Cannabis extracts), are authorized in some countries for therapeutic purposes as a second-choice approach (when conventional therapies have failed) for a certain number of clinical conditions such as pain and inflammation, epilepsy, anxiety disorders, nausea, emesis, and anorexia, among others. The present review will synthetize the beneficial properties of hemp and hemp derivatives in animal nutrition and therapeutics.

Pembuatan film plastik biodegradable dari limbah kulit kopi dengan penambahan kitosan/gliserol

Biodegradable plastic production has been developed for a long time by researchers. Data from Ministry of Industry in 2017 stated Indonesia's plastic production reached 3.9 million tons/ year. In this study, the raw materials used came from untapped waste, namely coffee skin, biodiesel-waste glycerol and shrimp-shells chitosan. In this research, biodegradable plastic films have been produced with the addition of glycerol and coffee skin waste with chitosan concentration variations of 0, 2, 4, 6, and 8%. After the optimum conditions were obtained by comparing the elongation and tensile strength values, then the variations in coffee skin waste were added with a weight of 0, 2, 4, 6, and 8 g. Tensile strength and elongation values with variations of chitosan were 0.2-1.87 MPa and 0.22-0.15%, respectively. Whereas the variation of tensile strength and elongation coffee skins were 1.8-0.27 MPa and 0.14-0.2%, respectively. The optimum conditions for producing biodegradable plastic films were obtained with variations of chitosan 4% and 2 g coffee skin with tensile strength and elongation values of 0.98 MPa and 0.16%. The tensile strength and elongation data produced from biodegradable plastic was still below the standard value of commercial plastic or synthetic plastic (HDPE) with values of tensile strength and elongation of 28.64 MPa and 6.5186% respectively.

Uncatalysed Polycondensation of Lactic Acid to Polylactic Acid Under Microwave Irradiation: Effect of Microwave Power

In this study, polycondensation of 88wt% lactic acid (LA) was performed by irradiating LA with microwave at different powers (P=250, 440, 715 and 900W) for 5 min, in the absence of a catalyst. The recovered products were analysed by attenuated total reflectance-infrared (ATR-IR) and thermogravimetric analysis (TGA). It was found that raising microwave power resulted in a significant increase in mass loss, even much higher than the water content of the fresh LA (12wt%). Such an observation was likely to be caused by two occurrences. The first is associated with the evaporation of 12wt% of water molecules in the fresh LA that escalated upon increasing microwave power. This is supported by ATR-IR analysis illustrating a decreasing trend in the intensity of O-H stretching band. The second is linked to the intensified polycondensation of LA to polylactic acid (PLA) when elevating microwave power, forming more ester bonds and consequently eliminating more water molecules. The increased formation ester bonds was evidenced by the shift in Tonset values towards higher temperatures, as exhibited by TGA profiles. As overall, the outcomes of this study could lead to a cost effective and energy saving production of biodegradable plastics, substituting the time-consuming conventional heating.

Optimisation on the production of biodegradable plastic from starch and cassava peel flour using response surface methodology

Biodegradable plastic is starch-based plastic that can be naturally decomposed by microorganisms. Cassava is one of the primary starch-producing plants. The increasing amount of cassava production increases cassava peel waste. Cassava peel has 50% of the starch content in the tuber. The factors that are affecting the production of biodegradable plastics are temperature and drying duration. This study aimed to obtain the optimum temperature and drying time to produce biodegradable plastics from starch and flour of cassava peel waste. Response Surface Methodology (RSM) with a Central Composite Design (CCD) method was employed. The experimental design included two factors and three responses. The first factor was the drying temperature (40 °C, 50 °C, and 60 °C) and the second factor was the drying duration (5 hours, 6 hours, and 7 hours). The responses measured were tensile strength, elongation, swelling and biodegradability. The study found that the optimum condition of the process was at the drying temperature of 57.79 °C and drying duration of 5 hours. At this optimum condition, the biodegradable plastic produced has the tensile strength of 2554.65 N/m2; elongation of 16.67%; and swelling of 124.17%. Biodegradation testing for 12 days resulted in a mass reduction of 58.30%.

Degradation Behaviors of Biodegradable Aliphatic Polyesters and Polycarbonates

Aliphatic polyesters and polycarbonates such as polylactide (PLA), polycaprolactone (PCL) and poly(propylene carbonate) (PPC), are well known as biodegradable, biocompatible and environmental-friendly polymeric materials, which have been widely used in various areas ranging from packaging to biomedical materials. The production and usage of biodegradable plastics can greatly alleviate the safety and environmental concerns because of the fairly short degradation periods and low toxicity of catabolite. During the degradation process of polymers, obvious changes appear in polymer structures and the physiochemical properties. Therefore, it is necessary to regulate and control the degradation behaviors and periods of biodegradable plastics such as polyesters and polycarbonates, which is significant for their more widespread popularization and applications. In this context, it is highly desirable to make a review contribution in this field so as to better understand the recent research progress on polymer degradation behaviors and kinetics, as well as the future prospect of biodegradable polymers. Herein, this paper reviews the research progress on the degradation behaviors of biodegradable polyesters and polycarbonates materials including PLA, PCL and PPC. Through an in-depth study of various internal/external factors, the degradation mechanism of these polymers is unraveled, which will motivate future studies into the synthesis of novel biodegradable polymers and the understanding of their degradation behavior on the molecular level.