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Biodegradable plastics were synthesized for the effective use of sago starch-extraction residue, which has been discarded as a waste. Two types of esterified sago starch-extraction residue, P-SP and L-SP, were obtained. It had black color for P-SP160 (esterified by palm oil) to light yellow color for L-SP80 (esterified by lauric acid) and showed high carbon content, ranging from 399.3 to 537.1 g kg−1. Biodegradable plastics from the residue, which had high esterification degree showed thermoplasticity and slower decomposition in Andisols in Japan and Inceptisols in Philippines. The esterification degrees of P-SP160 and L-SP were 3.23 and 2.95 to 5.18 mmol g−1, respectively. In addition, L-SP80 exhibited the most appropriate thermal softening behavior by heating. The cumulative decomposition of P-SP160 in Andisols and Inceptisols showed 16.7 and 32.8% of total carbon during 31 day of the incubation. On the other hand, the decomposition rates of L-SP80 in Andisols and Inceptisols were less than 10% of total carbon during 31 day of the incubation. The addition of triacetin as plasticizer to P-SP160 and L-SP80 remarkably influenced the decomposition rate of both molded P-SP160 and L-SP80. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Advances in science and technology have resulted in the rapid development of modern society, which is clearly unsustainable because of the strain it places on current resources. The energy and materials needed to sustain the present society are derived primarily from non-renewable fossil resources, which will be depleted at some point. Plastics are one example of an important commodity in the modern lifestyle. While plastics are undoubtedly superior materials in terms of their costs, processability and functional properties, they are currently derived from fossil resources and they are not readily assimilated by the various ecosystems upon disposal. The search for biodegradable plastics that are derived from renewable resources has been ongoing since the 1970s. Two of the most promising biobased plastics, i. e., polylactic acid and polyhydroxyalkanoates, have received much attention as potential alternatives to existing processes. This article will discuss the current status and sustainability of these two next generation biobased plastics by taking into consideration the raw materials required, as well as the post-consumption effects of these materials on the environment. In addition, important issues surrounding the development and sustainability of biobased and biodegradable plastics will be highlighted.

One of the conventional methods to develop biodegradable plastics at a reasonable cost is manufacturing the blend of expensive polycaprolactone (PCL) and lower-priced starch. However, past studies have shown that the amount of starch blended with plastics is relatively small and the dynamic properties are not sufficiently improved. This study focuses on the improvement of physical properties of starch, including thermal plasticity, compatibility with PCL and dynamic properties. Starch was blended with glycerine and water to achieve thermal plasticity and improve compatibility with PCL. Addition of maleic anhydride to PCL improved compatibility, which resulted in improved dynamic properties. Addition of clay results in dispersed thermo plastic starch, which improves compatibility with PCL. In addition, it was clarified that addition of clay accelerates the positive effect of electron irradiation on the blend. Copyright © 2006 John Wiley & Sons, Ltd.

Condensed tannins derived from Pinus radiata bark have been esterified and added to biodegradable plastics as extrusion compounded functional plastic additives. The presence of longer alkyl chain hexanoate esters promoted tannin miscibility in the commercial polyesters Bionolle™ and Biopol™ whereas short chain acetate esters tended to remain as discrete domains, acting as fillers in the processed plastics. In the aliphatic polyester Bionolle the presence of tannin esters at typical plastic additive loadings did not alter plastic mechanical properties whereas at 5% content in Biopol the tannin-additives reduced both flexural and tensile properties. Similarly tannin esters do not alter the melt or glass transition temperatures of the polyesters, but tannin hexanoate at 5% can influence the crystallization temperatures. Artificially aging plastics realized the functionality these plant extracts can impart to plastics in acting to reduce ultraviolet (UV)-induced plastic degradation. Results indicate the tannin-additives likely provide a stabilising role through inhibiting UV penetration into the plastic, with color analysis suggesting the tannin moiety itself was sacrificial and preferentially degrading. The imparted UV stability was linked to the dissolution of tannin esters in the plastic with longer chain esters providing greater protection against UV degradation. Tannin esters showed potential as functional additives for biodegradable polymers enhancing the UV stability of the plastic. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41626.

This work describes the properties of plastics made from partially denatured proteins produced by the animal coproduct (rendering) industry and these plastics' fabrication. Specifically, plastic samples from partially denatured feathermeal protein were successfully produced by a compression-molding process. The modulus (stiffness) of the material obtained was found to be comparable with that of commercial synthetic materials, such as polystyrene, but was found to have lower toughness characteristics, which is a common phenomenon among plastics produced from animal and plant proteins. A reversible stress–strain property was observed over the yield region. Plastic-forming conditions for undenatured animal proteins, such as albumen and whey proteins, were also formulated for fabricating plastics out of these proteins' blends with feathermeal proteins. The resultant plastic samples that were developed of biomacromolecular blends, such as feathermeal/whey and feathermeal/albumen, demonstrated improved mechanical properties, specifically tensile strength, when compared with neat plastics from feathermeal proteins. The values for the stiffness of the feathermeal/whey blends deviated from simple mixing rule and showed a synergistic effect. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Biodegradable plastic composites were subjected to prolonged soaking and freezing treatments to assess the effects on the mechanical performance. Radiata pine flour and thermomechanical pulp fibers were used as fillers at various addition levels in three different commercial polymer matrices. Two were bioderived, one oil-derived, each with different hydrophobicities. Depending on the nature of the biodegradable polymer matrix, the rates and extents of water uptake were found to be either enhanced or reduced by the wood-derived fillers. Although the higher aspect ratio of the pulp fibers improved mechanical performance, relative to the wood flour, water uptake was also significantly enhanced in some cases. POLYM. COMPOS. 27:323–328, 2006. © 2006 Society of Plastics Engineers

Biodegradable plastics were produced from sweet potato pulp (SPP) and cationic starch (CS) or chitosan composite (CC) by compression molding and their mechanical properties were tested. A universal testing machine, Rockwell hardness tester, and Izod impact tester were used for testing the mechanical properties (flexural strength, Rockwell hardness, and Izod strength) of the plastics. A central composite second-order design was used to study the effects of temperature, time, and moisture content on the flexural strength, Rockwell hardness, and Izod strength of SPP/CS and SPP/CC blended plastics. The flexural strength, Rockwell hardness, and Izod strength of SPP-based plastics was 101.1–305.9 kg/cm2, R29.0–R96.7, and 0.6–3.0 kg cm cm−2, respectively. Regression analysis predicted the optimal mechanical properties (flexural strength, Rockwell hardness, and Izod strength) to be attained with a 150–160°C temperature, 15–20-min reaction time, and 20–23% moisture content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 423–434, 2002

Eight kinds of biodegradable plastics were examined in controlled laboratory composting conditions for their degradability. Ultimate degradability, defined as a molar ratio of carbon loss as CO2 to the carbon contained in the plastic particles or pellets that have been added to the composting material, was calculated. The ultimate degradability of the biodegradable plastic was found to be dependent strongly on the kind of the plastic. The degradability of the eight kinds of plastics tested herein ranged from a small percentage to approximately 65% over the 8-day period of the 50°C composting.

The use of biodegradable polymers in animal nutrition can be considered not only as a possible way of waste recycling but could also be beneficial in the derivation of animal products from the conversion of these energy-rich substances within the nutritional chain. However, earlier studies with swine and sheep as well as in vitro studies have shown a poor digestibility of untreated biodegradable plastics (Kunkel and Seo 1994; Forni et al. 1999a,b). The low accessibility of the polymeric chains, particularly if only coarsely milled, to the gastric juices, enzymes and gastrointestinal micro-organisms of farm animals, and the relatively short incubation time during the passage through the digestive tract obviously limit the degradation of these biodegradable polymers. Therefore, the present study focused on the effects of pretreatment and of increasing the dietary proportion of the biodegradable plastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). PHBV is an aliphatic biodegradable polymer produced by bacteria (de Koning et al. 1996). Pretreatment with NaOH was chosen to reduce the chain length and to form absorbable monomers such as β-hydroxybutyrate, a natural metabolite in the digestive turnover and metabolism of ruminants. NaOH is an inexpensive and effective substance for breaking down PHBV, which was found to increase the apparent PHBV digestibility by 37 % in swine (Forni et al. 1999a). In addition, NaOH pretreatment is commonly used in ruminant nutrition to enhance the digestibility and intake of straw and poor quality hay which are both rich in biological polymers such as cellulose and lignin (Flachowsky 1987).

Research on starch-based biodegradable plastics began in the 1970's and continues today at the National Center for Agricultural Utilization Research (NCAUR) in Peoria, IL. Technology has been developed for producing extrusion blown films and injection molded articles containing 50% and more of starch. Extrusion processing of compositions containing starch and other natural polymers to provide totally biodegradable plastics is being investigated. Starch grafted with thermoplastic side chains is under commercial development to provide injection molded items with a broad range of compositions and properties. The mechanism of biological degradation and the rate and extent of biodegradation of starch containing plastics in various environments is studied to enhance development and acceptance of biodegradable plastics.

In this paper, the approach of biodegradation to reduce the environmental impact of plastic wastes is reviewed. The mechanism of biodegradation and the processing and applications of these materials are also discussed in relation to the structural characters of their molecules. The synthetic biodegradable materials such as starch based biodegradable materials are compared with naturally occurring biodegradable materials such as poly(hydroxy butyrate) (PHB) in terms of their applications, processing difficulty, and degradation mechanism. The future trends of these materials are anticipated.

Introduction Historical Outline Plastics from Cellulose Acetate Plasticization of CA with Dibasic Acid Anhydrides and Monoepoxides during Melt-processing, and Their Biodegradabilities Cellulose Acetate Plasticized by Grafting with Cyclic Esters Plastics from Lignocellulose and Applications to Biodegradable Polymers Plasticization of Wood by Benzylation and Blending with Polycaprolactone Bio- and Photo-degradabilities of BzW and BzW/PCL Composites Production Outlook and Perspectives Patents Keywords: biodegradable polymers from biomass; cellulose; lignocellulose; thermoplasticization; wood plasticization; external plasticization; blend; compatibilizer; plasticizer; bleeding; internal plasticization; cellulose derivatives; nitrocellulose; cellulose acetate; graft copolymerization; graft polymer; homopolymer; melt-processing; molding; biodegradation; mineralization; polyurethane; regenerated cellulose; interpenetrating polymer network

Introduction Scope Applications Performance Raw Material Base Manufacture Biodegradation Assessment Product Use in Practice The Comprehensive Approach: Ecological Relevance Recovery and Disposal Legal Framework Consequences and Future Developments Outlooks and Perspectives Acknowledgements Keywords: biodegradation; Biowaste Ordinance; blend system; certification; climate protection; composting/digestion; comprehensive approach; consumer behavior; ecoefficiency; ecological relevance; ecotoxicity; energy expenditure; fossil resources; innovation; legislation; life-cycle analysis; mechanism of degradation; packaging; Packaging Ordinance; plastics production; policy; product life cycle; product safety; raw material; recovery; recycling; renewable resources; standardization; thermoplasticity; use effect; use phase; waste management

Background This work evaluated the performances of protein-based bioplastics obtained from black soldier fly (Hermetia illucens) prepupae. Protein films were synthesized by film casting, using both the whole proteins and their soluble fraction at pH = 10. The effects of glycerol as a plasticizer and of citric acid as a mild crosslinker on film properties were also evaluated. Results Films obtained using the soluble protein fraction were the strongest, as well as the most homogeneous and transparent ones. Protein mild crosslinking improved film tensile properties, especially in films obtained with the whole protein fraction. Non-crosslinked samples had a high affinity with water while crosslinking almost eliminated the ability of films to absorb water. All protein-based films proved to be effective barriers to red light (transmittance less than 2%). Conclusions Bioplastics derived from black soldier fly prepupae may find applications in the agricultural sector (biodegradable pots, mulching films, utensils) and deserve to be tested for food and non-food packaging. © 2021 Society of Chemical Industry.

Demand for antimicrobial packaging films is growing due to public attention to food safety. The structures and properties of gellan gum-guar gum blend films incorporated with nisin were investigated in this paper. Fourier transform infrared spectroscopy, rheological analyses showed intermolecular interactions among gellan gum, guar gum, and nisin. Furthermore, scanning electron microscopy and thermogravimetric analysis also indicated higher compatibility of the blend film components and better thermal stability than the gellan gum film. Tensile strength (TS), elongation at break (EAB) and water vapor permeability (WVP) of the blend films were enhanced with the addition of guar gum. The TS of the blend film reached 2.89 × 103 MPa, the EAB increased to 67.99%, and the WVP increased to 1.80 × 10-5 g/mm·s·Pa. Additionally, the film with nisin had antibacterial activity for Bacillus subtilis. The results demonstrated that a homogenous and smooth antimicrobial film with gellan gum, guar gum, and nisin could be a good option of antimicrobial packaging film for food preservation. PRACTICAL APPLICATION: This work investigated blend package films of gellan gum and guar gum incorporated with nisin. The results showed compatibility and thermal stability of the film were improved with adding a certain amount of guar gum, and also antibacterial activity for Bacillus subtilis of the blend film with nisin. Therefore, it can be used to the development of antimicrobial packaging films.

Electrospinning is a fabrication technique to generate three dimensional scaffolds with a fiber structure that imitates extracellular matrix for tissue engineering constructs. The versatile characteristics of the electrospinning process yields designer scaffolds made of biodegradable polymers or natural proteins with controllable fiber diameters, biodegradation, and mechanical properties. A limitation of conventional electrospun scaffolds is the dense fiber packing with low porosity that leads to poor cell infiltration. Electrospraying sacrificial polyethylene oxide (PEO) microparticles in combination with electrospun scaffolds are a method to increase porosity. We report the effectiveness of electrospraying PEO microparticles to increase porosity of the most commonly used biodegradable polymers: polyglycolic acid (PGA), poly (lactic-co-glycolic) acid (PLGA), and polycaprolactone (PCL). The biodegradable polymer electrospun scaffolds with the sacrificial PEO microparticles were found to have improved cell proliferation and infiltration with human fibroblasts compared to conventional electrospun scaffolds. The mechanical properties of the more robust PGA and PLGA had minor changes, but the more elastic PCL was observed to be weaker and less stiff after the removal of the PEO microparticles. Therefore, this study found PEO microparticles can increase porosity and cell infiltration with stable mechanical properties for a wide variety of biodegradable polymers in electrospun scaffolds.

The major resolution of the study was to develop a dynamic form of natural biopolymer material to improve the wound healing by inhibition of biofilm formation on the surface. The extraction of collagen was effectively prepared from Scomberomorus lineolatus fish skin. Lyophilized collagen sheet was liquefied in 0.5M acetic acid to form acidic solubilized collagen (ASC) for further analysis. Physicochemical characterization of ASC was performed by various techniques using a standard protocol. The yield of ASC form S.lineolatus is higher (21.5%) than the previous reported studies. The effect of collagen solubility is gradually decreases with increasing concentration of NaCl and collagen is mostly soluble in acidic pH conditions. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of ASC contains α chain composition of α1 and α2 subunits and was characterized as type I collagen. Ultraviolet absorption was regulated as the appropriate wavelength to optimize the collagen. Fourier-transform infrared spectroscopy and X-ray diffraction confirmed that the isolated collagen is a triple-helical structure. The biofilm formation of Pseudomonas aeruginosa was significantly reduced by collagen incorporated with isolated 3,5,7-trihydroxyflavone (collagen-TF) sheet up to 70%. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay executed on fibroblast cell lines (L929) shows that the collagen-TF sheet was 100% compatible to enrich the cell adhesion and proliferation. The current study was the first report to extract, purify, and characterize ASC from S. lineolatus fish skin and characterize as type I collagen. Based on the result, we design the natural biodegradable collagen loaded with TF compound (collagen-TF) for antibiofilm properties. Compared with different sources of polymer, fish skin collagen is more effective and can be used as a biopolymer sheet for wound healing, food, drug delivery, tissue engineering, and pharmaceutical application.

This study investigates the mechanical properties and in vitro cytotoxicity of two-dimensional (2D) graphene oxide nanoribbons and nanoplatelets (GONRs and GONPs) reinforced porous polymeric nanocomposites. Highly porous poly(propylene fumarate) (PPF) nanocomposites were prepared by dispersing 0.2 wt % single- and multiwalled SONRs (SWGONRs and MWGONRs) and GONPs. The mechanical properties of scaffolds were characterized using compression testing and in vitro cytocompatibility was assessed using QuantiFlour assay for cellularity and PrestoBlue assay for cell viability. Immunofluorescence was used to assess collagen-I expression and deposition in the extracellular matrix. Porous PPF scaffolds were used as a baseline control and porous single and multiwalled carbon nanotubes (SWCNTs and MWCNTs) reinforced nanocomposites were used as positive controls. Results show that incorporation of 2D graphene nanomaterials leads to an increase in the mechanical properties of porous PPF nanocomposites with following the trend: MWGONRs > GONPs > SWGONRs > MWCNTs > SWCNTs > PPF control. MWGONRs showed the best enhancement of compressive mechanical properties with increases of up to 26% in compressive modulus (i.e., Young's modulus), ~60% in yield strength, and ~24% in the ultimate compressive strength. Addition of 2D nanomaterials did not alter the cytocompatibility of porous PPF nanocomposites. Furthermore, PPF nanocomposites reinforced with SWGONRs, MWGONRs, and GONPs show an improvement in the adsorption of collagen-I compared to PPF baseline control. The results of this study show that 2D graphene nanomaterial reinforced porous PPF nanocomposites possess superior mechanical properties, cytocompatibility, and increased protein adsorption. The favorable cytocompatibility results opens avenues for in vivo safety and efficacy studies for bone tissue engineering applications. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 1143-1153, 2019.

Background The article reviews the recent developments in bioplastic food packaging. Several bioplastic materials (polylactide, polyhydroxyalkanoates, and starch) have been successfully converted into food packaging using conventional plastic conversion technologies including extrusion, injection molding, and compression molding. Recently, bioplastic packaging has been developed into active packaging which can either control the release of active ingredients or scavenge undesirable substances. This review emphasizes the advances in bioplastic packaging with regard to active packaging applications and applications requiring gas and water barrier. Results The review shows that antioxidant and antimicrobial functions are major developments for the control-release application in bioplastic packaging. Factors affecting the release of active ingredients have been reviewed. The sorption of low molecular weight substances such as humidity, aromas, and gases, also affects the properties of packaging materials. Some patents are available for oxygen-scavenging bioplastic packaging. Moreover, improved high-barrier packaging technologies (modified polymer, coating, and lamination) have been developed to increase the shelf-life of food products. Conclusion The finding shows that the development of bioplastic into food packaging included control-release (desorption), scavenging (absorption) and permeation technologies. © 2018 Society of Chemical Industry.

Being a major component of bone tissue, hydroxyapatite is the most investigated calcium phosphate in the design and development of bone implants. The high brittleness and poor load-bearing properties have led researchers to manipulate hydroxyapatite performance by applying polymer or metal materials. The present study focuses on biomimetic approach of the hydroxyapatite synthesis from the cuttlefish bone in order to preserve highly porous structure. The low stiffness of hydroxyapatite scaffold was altered by thin polycaprolactone/poly(lactic acid) coating, resulting in remarkably 18-fold increase of Young's modulus. The mechanical test revealed that poly(lactic acid) increases the stiffness of composite scaffolds which depends on the polycaprolactone/poly(lactic acid) volume ratio. The composite scaffolds are bioactive supporting the deposition of new calcium phosphates when incubated in simulated physiological medium for 21 days. Moreover, the culture of human embryonic kidney cells indicated non-cytotoxicity of the composite scaffolds with emphasis on the cell proliferation during three days of culture. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 197-204, 2019.

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Background/purpose The plastic microbeads, used in many cleansers, will be banned in cosmetic and personal care products within 2017 since they are non-degradable and can disturb the living organisms in water reservoirs. Various choices of biodegradable beads are commercially available, but their efficacy has not been proven yet. This study aimed to compare the cleansing efficacy in dirt and sebum removal aspects of three types of exfoliating beads. Methods The gel scrubs with polyethylene (PE) beads, mannan beads or wax beads, were formulated and evaluated for their stability. The in vivo evaluation was done in 38 healthy volunteers and the skin irritation, efficacy for dirt and sebum removal were measured by Mexameter®, Colorimeter®, and Sebumeter®, respectively. Results The selected gel scrubs did not cause an irritation in any volunteers. The differences in dirt residues between before and after scrubbing were not statistically significant among three gel scrubs and the similar result was also reported in the sebum removal study. Conclusion All gel scrubs demonstrated the comparable cleansing efficacy in term of dirt and sebum removal. Thus, mannan beads and wax beads may be replaced non-biodegradable PE beads to achieve the similar cleansing effect.

Chirality is one of the most fascinating and ubiquitous features in nature, especially in biological systems. The effects of chiral surfaces, especially in combination with degradable materials of good biocompatibility, on stem cell behaviors has not yet been tackled. In this communication, the chiral monomers N-acryloyl-l(d)-valine (l(d)-AV) are synthesized and are polymerized to obtain chiral (l(d)-PAV-SH) oligomers, which are covalently immobilized onto electron-deficient poly(propylene fumarate) polyurethane (PPFU) via Michael addition. The PPFU-l-PAV can interact more strongly and actively with bone marrow stem cells (BMSCs) than PPFU-d-PAV, leading to a larger cell spreading area, faster migration velocity, and stronger osteodifferentiation tendency.

Poly ((ethylene oxide)-b-(propylene oxide)-b-(ethylene oxide)) triblock copolymers commonly known as poloxamers or Pluronics constitute an important class of nonionic, biocompatible surfactants. Here, a method is reported to incorporate two acid-labile acetal moieties in the backbone of poloxamers to generate acid-cleavable nonionic surfactants. Poly(propylene oxide) is functionalized by means of an acetate-protected vinyl ether to introduce acetal units. Three cleavable PEO-PPO-PEO triblock copolymers (Mn,total = 6600, 8000, 9150 g·mol(-1) ; Mn,PEO = 2200, 3600, 4750 g·mol(-1) ) have been synthesized using anionic ring-opening polymerization. The amphiphilic copolymers exhibit narrow molecular weight distributions (Ð = 1.06-1.08). Surface tension measurements reveal surface-active behavior in aqueous solution comparable to established noncleavable poloxamers. Complete hydrolysis of the labile junctions after acidic treatment is verified by size exclusion chromatography. The block copolymers have been employed as surfactants in a miniemulsion polymerization to generate polystyrene (PS) nanoparticles with mean diameters of ≈200 nm and narrow size distribution, as determined by dynamic light scattering and scanning electron microscopy. Acid-triggered precipitation facilitates removal of surfactant fragments from the nanoparticles, which simplifies purification and enables nanoparticle precipitation "on demand."

To enhance drug cellular uptake, a biodegradable terpolymer is synthesized using taurine, N,N-Bis (acryloyl) cystamine, and dodecylamine as raw materials by Michael addition terpolymerization. The terpolymer is transformed to zwitterionic nanoparticles (NPs) through self-assembly. The surface charge of the NPs is convertible from negative at pH 7.4 to positive at pH 6.5, which endows the NPs' excellent nonfouling feature in bloodstream and effective uptake in tumor cells. The NPs display varied morphologies from solid micelles to polymersomes and nanorods depending on molar ratios of the structural units involved. The NPs can be biodegraded in l-glutathione (GSH) solution due to the split of disulfide bonds in main chains of the terpolymers. The NPs demonstrate good pH/reducing responsiveness in drug delivery and can be potentially used as anticancer drug vehicles for enhancement of cellular uptake of anticancer drug.

This paper describes a simple system for multi-agent delivery. The system consists of a biodegradable polymer particle with a hollow interior, together with a hole on its surface that can be completely or partially sealed via thermal annealing. A hydrophobic dye, Nile-red, entrapped within the shell of hollow particles presents a sustained release behavior while methylene blue, a hydrophilic model agent, encapsulated in the hollow interior shows a fast release manner. The release profiles of the probes can be further independently controlled by encapsulating methylene blue-loaded polymer nanoparticles, instead of free dye, in the hollow particle with a small hole on its surface.

Biodegradable printed circuit boards based on water-soluble materials are demonstrated. These systems can dissolve in water within 10 mins to yield end-products that are environmentally safe. These and related approaches have the potential to reduce hazardous waste streams associated with electronics disposal.

The encapsulation of cells into polymeric microspheres or microcapsules has permitted the transplantation of cells into human and animal subjects without the need for immunosuppressants. Cell-based therapies use donor cells to provide sustained release of a therapeutic product, such as insulin, and have shown promise in treating a variety of diseases. Immunoisolation of these cells via microencapsulation is a hotly investigated field, and the preferred material of choice has been alginate, a natural polymer derived from seaweed due to its gelling conditions. Although many natural polymers tend to gel in conditions favorable to mammalian cell encapsulation, there remain challenges such as batch to batch variability and residual components from the original source that can lead to an immune response when implanted into a recipient. Synthetic materials have the potential to avoid these issues; however, historically they have required harsh polymerization conditions that are not favorable to mammalian cells. As research into microencapsulation grows, more investigators are exploring methods to microencapsulate cells into synthetic polymers. This review describes a variety of synthetic polymers used to microencapsulate cells. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 846–859, 2015.

Background The optimal duration of dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation remains controversial. The primary aim of our study was to evaluate the impact of optimal DAPT duration on bleeding events between 6 and 12 months after biodegradable polymer-coated DES implantation. The secondary aim is to determine the predictors and prognostic implications of bleeding. Methods This study is a post hoc analysis of the Multi-Center Registry of EXCEL Biodegradable Polymer Drug Eluting Stents (CREATE) study population. A total of 2,040 patients surviving at 6 months were studied, including 1,639 (80.3%) who had received 6-month DAPT and 401 (19.7%) who had received DAPT greater than 6 months. Bleeding events were defined according to the bleeding academic research consortium (BARC) definitions as described previously and were classified as major/minor (BARC 2–5) and minimal (BARC 1). A left censored method with a landmark at 6 months was used to determine the incidence, predictors, and impact of bleeding on clinical prognosis between 6 and 12 months. Results At 1-year follow-up, patients who received prolonged DAPT longer than 6 months had a significantly higher incidence of overall (3.0% vs. 5.5%, P = 0.021) and major/minor bleeding (1.1% vs. 2.5%, P = 0.050) compared to the patients who received 6-month DAPT. Multivariate analysis showed that being elderly (OR = 1.882, 95% CI: 1.109–3.193, P = 0.019), having diabetes (OR = 1.735, 95% CI: 1.020–2.952, P = 0.042), having a history of coronary artery disease (OR = 2.163, 95% CI: 1.097–4.266, P = 0.026), and duration of DAPT longer than 6 months (OR = 1.814, 95% CI: 1.064–3.091, P = 0.029) were independent predictors of bleeding. Patients with bleeding events had a significantly higher incidence of cardiac death, myocardial infarction, target lesion revascularization, and stent thrombosis. Conclusions Prolonged DAPT (greater than 6 months) after biodegradable polymer-coated DES increases the risk of bleeding, and is associated with adverse cardiac events at 1-year follow-up. (J Interven Cardiol 2014;27:119–126)

In this study proteins extracted from prepupae of Hermetia illucens, also known as black soldier fly, are investigated as promising base for a new type of bioplastics for agricultural purposes. Design of experiments techniques are employed to perform a rational study on the effects of different combination of glycerol as plasticizer, citric acid as cross-linking agent and distilled water as solvent on the capability of proteins to form a free-standing film through casting technique, keeping as fixed the quantity of proteins. Glycerol shows interesting properties as plasticizer contributing to the formation of homogenous and free-standing film. Moreover, mechanical and thermal characterizations are performed to estimate the effect of increasing amounts of proteins on the final properties and thickness of the specimens. Proteins derived from H. illucens can be successfully employed as base for bioplastics to be employed for agricultural purposes.

tar-like polymers are one of the smallest systems in the class of core crosslinked polymeric nanoparticles. This article reports on a versatile, straightforward synthesis of three-arm star-like polypept(o)ide (polysarcosine-block-polylysine) polymers, which are designed to be either stable or degradable at elevated levels of glutathione. Polypept(o)ides are a recently introduced class of polymers combining the stealth-like properties of the polypeptoid polysarcosine with the functionality of polypeptides, thus enabling the synthesis of materials completely based on endogenous amino acids. The star-like homo and block copolymers are synthesized by living nucleophilic ring opening polymerization of the corresponding N-carboxyanhydrides (NCAs) yielding polymeric stars with precise control over the degree of polymerization (Xn = 25, 50, 100), Poisson-like molecular weight distributions, and low dispersities (Đ = 1.06–1.15). Star-like polypept(o)ides display a hydrodynamic radius of 5 nm (μ2 < 0.05) as determined by dynamic light scattering (DLS). While star-like polysarcosines and polypept(o)ides based on disulfide containing initiators are stable in solution, degradation occurs at 100 × 10–3m glutathione concentration. The disulfide cleavage yields the respective polymeric arms, which possess Poisson-like molecular weight distributions and low dispersities (Đ = 1.05–1.12). Initial cellular uptake and toxicity studies reveal that PeptoStars are well tolerated by HeLa, HEK 293, and DC 2.4 cells.

Non-value agrifood byproducts are rich in biomolecules such as proteins and polysaccharides, and possess film-forming ability, motivating their use in the development of biodegradable plastics. This work studied the feasibility of using locust bean milling-derived dust (LBMD) as a source of biomolecules suitable for developing biodegradable plastics.LBMD is composed of 56% protein, 28% carbohydrate, 10% moisture, 6% lipid, and 2% ash. In addition, phenolic compounds are also present. The carbohydrates are mainly composed by (1 → 4)-mannose, (1 → 4,6)-mannose, and t-galactose glycosidic linkages. Depending on the LBMD concentration used, when employed in casting biodegradable plastics, LBMD yields transparent yellowish bioplastics with 90% elongation at break and surface water contact angles ranging from 60° to 90°. Additionally, LBMD-based bioplastics display antioxidant activity, inhibiting cationic 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals up to 61% in just 24 h. LBMD-based bioplastics are disintegrated when incubated on the soil surface for 34 weeks, perhaps acting as a soil nutrient.LBMD represents a potential source of biomolecules for producing transparent, flexible, water tolerant, antioxidant, and biodegradable bioplastics, opening up opportunities to implement a novel circular strategy to valorize this locust bean industry byproduct. © 2022 Society of Chemical Industry.

Biodegradable plastics have been increasingly used as a solution to the problem of plastic pollution in recent years. However, there are few studies on the negative effects of biodegradable microplastics. Triclosan, a widely used disinfectant, is a highly toxic substance. In the present study, the adsorption and desorption processes of triclosan on a type of biodegradable plastics, polyhydroxybutyrate (PHB), were investigated and also compared with one conventional plastic type, polyethylene. The adsorption equilibrium quantities of polyethylene and PHB were 3431.85 and 9442.27 μg/g, respectively. The adsorption rate and equilibrium adsorption capacity of triclosan on PHB are much higher than on polyethylene. Physical adsorption of triclosan on PHB and polyethylene microplastics may play a dominant role in this process. The desorption hysteresis indices are all less than zero; this indicates that triclosan is easily released from PHB and polyethylene microplastics under physiological conditions. Our results indicate that biodegradable PHB microplastics are stronger carriers for triclosan than the conventional polyethylene microplastics in the aquatic environment. Environ Toxicol Chem 2021;40:72-78. © 2020 SETAC.

Landfill sites have become overburdened by large volumes of disposable low density plastic waste from packaging and polymers such as disposable diapers. This has adversely affected the number and capacity of landfill sites available for the disposal of all grades of trash and also the long-term mechanical stability of landfill sites receiving potentially degradable and biodegradable plastics and polymers capable of toxic, flammable, and environmentally harmful gas generation. These limitations of landfilling polymers and plastics helped precipitated the waste management era, where alternative approaches were and are still being considered and developed to limit plastic disposal problems. Some of these alternatives include limiting or eliminating plastic landfill disposal entirely, controlled landfilling in bioreactors to harvest gas, recycling, incineration, and biodegradation under controlled environmental conditions such as composting. The development of suitable polymers and plastics and the implementation of these alternatives is a slow process, and huge amounts of conventional plastics and polymers still enter landfill sites every year. This article updates the issue, complicated scientifically and legislatively, as we strive for environmental harmony in our lifestyles. Currently, there is limited evidence on waste polymers and plastics as to their ultimate fate—recalcitrance, degradation, or biodegradation in landfills. Longer term, our understanding of landfill processes is improving as the ASTM strives to develop improved standards for estimating the fate of plastics and polymers in landfills in concert with notable scientific studies at various academic centers. Keywords: plastics in trash; degradable plastics; biodegradable plastics; addition polymers; condensation polymers

A promising strategy to alleviate the plastic pollution from traditional petroleum-based plastics is the application of biodegradable plastics, in which polyhydroxyalkanoates (PHAs) have received increasing interest owing to their considerable biodegradability. In the PHAs family, poly(3-hydroxybutyrate-co-3-hydroxvalerate) (PHBV) has better mechanical properties, which possesses broader application prospects. With this purpose, the present study adopted Cupriavidus necator to synthesize PHBV utilizing volatile fatty acids (VFAs) as sole carbon sources. Results showed that the concentration and composition of VFAs significantly influenced the production of PHAs. Especially, even carbon VFAs (acetate and butyrate) synthesized only poly(3-hydroxybutyrate) (PHB), while the addition of odd carbon VFAs (propionate and valerate) resulted in PHBV production. The 3-hydroxyvalerate (3HV) contents in PHBV were directly determined by the specific VFAs compositions, in which valerate was the preferred substrate for 3HV accumulation. After optimization by response surface methodology, the highest PHBV accumulation achieved 79.47% in dry cells, and the conversion efficiency of VFAs to PHBV reached 40%, with the PHBV production of 1.20 ± 0.05 g/L. This study revealed the metabolic rule of VFAs converting into PHAs by C. necator and figured out the optimal VFAs condition for PHBV accumulation, which provides a valuable reference for developing downstream strategies of PHBV production in industrial applications in future.

The disposal of non-degradable plastics has increased exponentially as a result of poor recycling efficacy. The development of biodegradable plastics has become indispensable over the last two decades because of their origin from renewable resources. The potential interest in biodegradable plastics comes from the eco-friendly obliteration via microbial action which transforms the plastics into carbon dioxide and water resulting in a pollution-free natural system. Even though the lucrative interest lies in multiple areas, some of the properties such as brittleness, and poor thermal, mechanical and low gas barrier properties restrict their practical uses. The incorporation of nanoparticles in the polymer matrix or the fabrication of nanocomposites overcomes the shortcomings of the biodegradable polymers. To improve the aforementioned properties further, several approaches have been utilized, especially the incorporation of nanoparticles in the polymer matrix to prepare nanocomposites. One of the great advantages of nanoparticles is the ability to tune the rate of biodegradation (it is possible to both increase and decrease the rate as compared to that of the pure polymer) depending upon the need. Thus, chemical, physical and biological properties of the biodegradable polymers can be modified and controlled for sustainable applications in medicine and other areas. This review considers the major concerns of biodegradable polyesters and their nanocomposites, great details about the mechanism of their biodegradation, factors influencing their biodegradation and their applications in biomedical and packaging industries.

Bioplastics made with renewable resources are now ready for full commercial exploitation. Starch-based plastics are an important class of bioplastics used to make biodegradable products. Biodegradability can contribute to alleviating the waste problem of our current society. In this paper, three case studies based on the use of starch-based plastics are shown. Biodegradable products can both reduce the amount of waste produced and increase material recycling and landfill diversion. The products analysed and the main effects of shifting towards biodegradable plastics are examined next. By using biodegradable mulch film, waste passes from 400 up to ≈ 0 kg per mulched hectare. By using biodegradable catering items, the average recycling (including organic recycling) rate increases from ≈ 0 up to 50% whereas landfill diversion increases by 36% on average across EU-27. By shifting towards biodegradable carrier bags, a substantial reduction of contaminants present in bio-waste and screened off by composting plants results in an almost fivefold increase of bio-waste quality. The possibility of shifting from heterogeneous waste (non-biodegradable plastics + bio-waste) into homogeneous waste (biodegradable plastics + bio-waste) makes the use of bioplastics particularly beneficial for the waste management ecoprofile as shown by previous life cycle assessment studies available in literature. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.

Biodegradable plastics (GSD) based on soy dreg (SD) were prepared by compression-molding, with glycerol as the plasticizer and glutaraldehyde (GA) as the cross-linker. The structure and properties of the GSD sheets were investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA), scanning electron microscope (SEM), and tensile test methods. The results indicate that when GA content was 6.8%, the tensile strength (σb) of the sheet reached the maximum value of 14.5 MPa. Moreover, the strength and water resistance of the sheets coated with castor-oil-based polyurethane/nitrochitosan interpenetrating network (IPN) coating were significantly enhanced to 24.6 MPa in the dry state and 9.8 MPa in the wet state. Simultaneously, the test of biodegradability of the GSD sheet in a mineral salts medium containing microorganisms and agar proved that GSD could be fully biodegradable. This work has provided a novel way to utilize low-cost SD to prepare biodegradable plastics. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 422–427, 2003

Polyhydroxyfettsauren sind unverzweigte Polymere, die aus 1.000 — 30.000 Hydroxyfettsaureeinheiten bestehen. Die bekannteste PHF, Poly(3-Hydroxybuttersaure), Kurzform Poly(3HB), wird von Bakterien als Speicherstoff gebildet. Zahlreiche Bakterien und Pilze konnen PHF abbauen und als C-Quelle nutzen. PHF besitzen gute chemische und physikalische Eigenschaften wie UV- und Hydrolysebestandigkeit, die denen von Polypropylen sehr ahnlich sind. Es gibt Interesse seitens der Kunststoff verarbeitenden Industrie, diese Polyester beispielsweise als Rohstoffe fur biologisch abbaubare Verpackungen einzusetzen. In dem gut untersuchten Bakterium Ralstonia eutropha geht die Synthese von Poly(3HB) von Acetyl-CoA aus und benotigt insgesamt drei Schritte, fur die drei unterschiedliche Enzyme benotigt werden, namli β-Ketothiolase, Acetoacetyl-CoA-Reduktase sowie PHF-Synthase. Diese Enzyme werden durch drei Gene kodiert, die inzwischen kloniert worden sind. Damit wurde auch die Grundlage fur die Etablierung des PHF-Stoffwechsels in Pflanzen geschaffen. Die PHF-Produktion in Bakterien erfordert namlich die Zufuhr von externen Kohlenstoffquellen und ist deshalb nicht wirtschaftlich. Pflanzen dagegen gewinnen Energie durch Photosynthese und stellen daher eine interessante Alternative fur die PHF-Produktion dar. Auch fehlen den Pflanzen die Enzyme fur den PHF-Abbau und damit fur deren energetische Nutzung. Es ist gelungen, die Gene fur die Poly(3HB)-Synthese mittels Gentransfer in die Modellpflanze Arabidopsis thaliana zu ubertragen, die danach bis zu 40 mg/g Frischgewicht Poly(3HB)erzeugte. Dabei wurden die Gene stabil im Kerngenom integriert. Neuere Arbeiten zeigen, dass auch Nutzpflanzen auf die gleiche Weise transformiert werden konnen. Transgene Rapspflanzen speicherten bis zu 7%Poly(3HB)in der Trockenmasse. Derartige Pflanzen konnten eine interessante Anbaualternative fur die Landwirtschaft darstellen. So ist die Produktion von Pflanzen denkbar, die neben dem klassischen Ernteprodukt wie Starke oder Samenole auch Poly(3HB)produzieren. Allerdings ist es bis dahin noch ein langer Weg, weil Pflanzen selektiert werden mussen, die nicht nur die Eigenschaft der Poly(3HB)-Synthese stabil vererben, sondern auch unter hiesigen Produktionsbedingungen anbauwurdig sind. Crop plants are ultivated for producing starch, oils, proteins, sugar, fibres and other products. An increasing amount of these products is used as renewable resources for industrial purposes. But there is still a demand for new products with improved properties such as biodegradable plastics like polyhydroxyfatty acids (PHF) which cannot be found in the plant kingdom. PHF are linear polymers found as a major storage component in many bacterial species. Polyhydroxy-butyric acid, poly(3HB), is the most abundant representative of this class of polymers. Three enzymes have been identified from the bacterium Ralstonia eutropha responsible for poly(3HB)-synthesis. These enzymes are encoded by three different genes. PHF can be utilized by many microorganisms as carbon- and energy-source with the help of certain depo lymerases. PHF-storing plants fulfill the criteria as renewable resource for biodegradable plastics. Using Arabidopsis thaliana as a model plant, the poly(3HB)-metabolism has been established in plants after transformation with the three bacterial genes under the control of plant promotors. Transgenic plants have been selected accumulating up to 40% poly(3HB) dry weight. Recent data demonstrate that high amounts of poly(3HB) can also be stored in rape seed, the main oil producing rop for moderate limates. This offers the possibility to breed poly(3HB)-producing rop plants with full agronomical performance.

Recently the critical discussion about the preservation of natural resources and recycling has led to the renewed interest concerning biomaterials with the focus on renewable raw materials. Because of increasing environmental consciousness and demands of legislative authorities, use and removal of traditional composite structures, usually made of glass, carbon or aramid fibers being reinforced with epoxy, unsaturated polyester, or phenolics, are considered critically. Recent advances in natural fiber development, genetic engineering and composite science offer significant opportunities for improved materials from renewable resources with enhanced support for global sustainability. The important feature of composite materials is that they can be designed and tailored to meet different requirements. Since natural fibers are cheap and biodegradable, the biodegradable composites from biofibers and biodegradable polymers will render a contribution in the 21st century due to serious environmental problem. Biodegradable polymers have offered scientists a possible solution to waste-disposal problems associated with traditional petroleum-derived plastics. For scientists the real challenge lies in finding applications which would consume sufficiently large quantities of these materials to lead price reduction, allowing biodegradable polymers to compete economically in the market. Today's much better performance of traditional plastics are the outcome of continued RD however the existing biodegradable polymers came to public only few years back. Prices of biodegradable polymers can be reduced on mass scale production; and such mass scale production will be feasible through constant R&D efforts of scientists to improve the performance of biodegradable plastics. Manufacture of biodegradable composites from such biodegradable plastics will enhance the demand of such materials. The structural aspects and properties of several biofibers and biodegradable polymers, recent developments of different biodegradable polymers and biocomposites are discussed in this review article. Collaborative R&D efforts among material scientists and engineers as well as intensive co-operation and co-ordination among industries, research institutions and government are essential to find various commercial applications of biocomposites even beyond to our imagination.

Plastics have become an integral part of our contemporary life because of many desirable properties including durability and resistance to degradation. However, these nondegradable, petrochemicals-derived plastics accumulate in the environment at a rate of 25 million tons per year. Recently there is an interest in the development of a class of microbially produced bioplastics, e.g., polyhydroxyalkanoates (PHAs) which retain the desired physical and chemical properties of conventional synthetic plastics. Broader usage of biodegradable plastics in packaging and disposable products as a solution to the environmental problem would heavily depend on further reduction of costs and the discovery of novel biodegradable plastics with improved properties. In this paper, the microbial production of PHAs by activated sludge utilizing food industrial wastes is reported. The melting points of the products as well as the co-polymer composition of the products investigated by GC and NMR were compared. By use of activated sludge to convert the carbon source into PHAs not only environment-friendly bioplastics are produce, but also part of the problem of the disposal of municipal activated sludge is solved. The selection of food industrial waste as carbon resource can also further reduce the cost of production of PHAs.

Several companies have developed inherently biodegradable plastics based on starch and foam for loose-fill packaging material was the representing case. It is water soluble, but the change of the resilience and volume is less than several % when it is laid open at 32 °C, RH 70%. Starch-based polyvinylalcohol, aliphatic polyester, polycaprolactone biodegradable polymers were developed also. The PET fiber manufacturing companies have developed aliphatic polyester biodegradable plastics based on diol (butanediol, ethylene glycol) and diacid (succinic acid, adipic acid). The polymers have shown good mechanical properties and processibilities. They have succeeded to apply for injection, films, sheets, extrusion coatings, filaments, non-woven products, foams, and blow molding and lead this area in Korea. Polyhydroxybutyrate(PHB) and its copolymer were the first biodegradable polymer introduced in Korea. The gene cloning and recombinant technology was succeeded to produce PHB and PHB/V by E-coli and to yield the higher productivity than before. Lactic acid production and direct condensation polymerization of lactic acid is also being developed.

Biodegradable blend plastics such as polycaprolactone (PCL)-conventional plastics blends, PCL-polystyrene blend foams, PCL-poly-3-hydroxybutyrate (PHB) blends, PCL-raw cornstarch (CS) blends and PCL-CaCO3 blends were developed. It was suggested that the thermophilic composting of biodegradable plastics containing PCL was one of powerful technologies for recycling of biodegradable plastics. Furthermore, we tried to get useful products from biodegradable plastics by microbial fermentation processes. Polypropylene (PP)-CS blend and PCL-CS blend plastics were aerobically converted into ethanol by Bacillus polymyxa. PHB and PP-CS blend and PCL-CS blend plastics were anaerobically converted into some organic acids and methane gas by mixed microbial cultures with a methanogenic bacterium.

Introduction General Mechanism of Biodegradation, and Definitions Testing Methods General Principles in Testing Biodegradable Plastics Analytical Procedures for Monitoring Biodegradation Development of Standardized Biodegradation Tests Regulations Concerning Biodegradable Plastics Certification and Labeling of Biodegradable Plastics Keywords: anaerobic digestion; biocorrosion; biodegradable; carbon dioxide evolution; certification; clear-zone-test; compostable; controlled composting test; definitions; degradation in compost; degradation in soil; degradation mechanism; ecotoxicity; enzyme tests; labels; limit values; pass level; radiolabeling; regulations; respirometric test; standardization organizations; standards; test methods