Biodegradable Blends Research Articles

Manipulating Crystallization for Simultaneous Improvement of Impact Strength and Heat Resistance of Plasticized Poly(l-lactic acid) and Poly(butylene succinate) Blends.

Crystalline morphology and phase structure play a decisive role in determining the properties of polymer blends. In this research, biodegradable blends of poly(l-lactic acid) (PLLA) and poly(butylene succinate) (PBS) have been prepared by melt-extrusion and molded into specimens with rapid cooling. The crystalline morphology (e.g., crystallinity, crystal type and perfection) is manipulated by annealing the molded products from solid-state within a short time. This work emphasizes on the effects of annealing conditions on crystallization and properties of the blends, especially impact toughness and thermal stability. Phase-separation morphology with PBS dispersed particles smaller than 1 μm is created in the blends. The blend properties are successfully dictated by controlling the crystalline morphology. Increasing crystallinity alone does not ensure the enhancement of impact toughness. A great improvement of impact strength and heat resistance is achieved when the PLLA/PBS (80/20) blends are plasticized with 5% medium molecular-weight poly(ethylene glycol), and simultaneously heat-treated at a temperature close to the cold-crystallization of PLLA. The plasticized blend annealed at 92 °C for only 10 min exhibits ten-fold impact strength over the starting PLLA and slightly higher heat distortion temperature. The microscopic study demonstrates the fracture mechanism changes from crazing to shear yielding in this annealed sample.

Degradation and Stabilization of Poly(Butylene Adipate-co-Terephthalate)/Polyhydroxyalkanoate Biodegradable Mulch Films Under Different Aging Tests

The degradation and stability of biodegradable films determine the service length of mulch films in actual use. Most biodegradable polymers degrade too fast to meet the required durability of mulch films. The objective of this work is to investigate the degradation behaviors of poly(butylene adipate-co-terephthalate) (PBAT)/polyhydroxyalkanoate (PHA) blend mulch films. Several different types of stabilizers were incorporated in the biodegradable blends to provide protection for the PHA/PBAT films during thermal processing and aging on agricultural fields. The degradation process of the films was systematically studied under an Accelerated aging test (AAT) and a Soil aging test (SAT). Adding a UV stabilizer, or antioxidant to the mulch films led to significant improvement in the retention of mechanical properties of the films under both AAT and SAT. Morphological evolution of the films with or without a UV stabilizer as a function of aging times was studied by Scanning electron microscopy. The results of thermal properties and crystallinity revealed damage of crystalline structure of the films during AAT. Spectrocopic results indicated that the films underwent both hydrolysis and photodegradative chain scissions (Norrish Type I/II reactions and photo-oxidation). Two degradation mechanisms of the PBAT/PHA biodegradable mulch films were proposed.

Synthesis and Characterization of Biodegradable Blend based on LDPE/cassava stem nanofiber cellulose

Conventional plastic becomes trend topic due to its long degradation time and needs attention related to environmental problem. One type of plastic that is difficult to be degraded is LDPE. Some of the efforts done is to synthesize plastics with organic material so that it becomes biodegradable plastic. Cellulose is an organic material that is abundant in nature and can be used as a filler. This research aims to synthesis the biodegradable plastic films composted by nanocellulose – LDPE. Mechanical (UTM), water resistance and degradation test has been done. The properties of the biodegradable blend still meet the commercial LDPE standart. Even though the biocomposite based on LDPE-nanofiber cellulose can not totally degradable but it is can be used as a solution to reduce the degradation time of a plastic waste.

Characterization of the Paper Coated with Polyhydroxybutyrate/Ethyl Cellulose Blends

In this study, paper was surface-treated with biodegradable blends made from polyhydroxybutyrate (PHB) and ethyl cellulose (EC) in various ratios to prepare coated paper, whose surface structure, barrier properties, and mechanical properties were analyzed to evaluate its applicability as a packaging material. It was found that as the coat weight increased, a continuous and smooth coating layer was formed, and the barrier properties and mechanical strength of the coated paper improved. When paper was surface-treated with a mixture of PHB and EC, the uniformity of the coating layer was increased and barrier properties were improved compared with the case where only PHB or EC was used as a surface treatment. The tensile strength of the coated paper improved as the mixing ratio of EC increased, but there was no significant change in elongation except under the condition of surface treatment with EC alone. Consequently, it could be considered that when PHB was applied as a surface treatment material for paper, the addition of EC was effective in improving the physical properties required as a packaging material.

Morphology, Thermo-Mechanical Properties and Biodegradibility of PCL/PLA Blends Reactively Compatibilized by Different Organic Peroxides.

Reactive blending is a promising approach for the sustainable development of bio-based polymer blends and composites, which currently is gaining more and more attention. In this paper, biodegradable blends based on poly(ε-caprolactone) (PCL) and poly(lactic acid) (PLA) were prepared via reactive blending performed in an internal mixer. The PCL and PLA content varied in a ratio of 70/30 and 55/45. Reactive modification of PCL/PLA via liquid organic peroxides (OP) including 0.5 wt.% of tert-butyl cumyl peroxide (BU), 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (HX), and tert-butyl peroxybenzoate (PB) is reported. The materials were characterized by rotational rheometer, atomic force microscopy (AFM), thermogravimetry (TGA), differential scanning calorimetry (DSC), tensile tests and biodegradability tests. It was found that the application of peroxides improves the miscibility between PCL and PLA resulted in enhanced mechanical properties and more uniform morphology. Moreover, it was observed that the biodegradation rate of PCL/PLA blends reactively compatibilized was lower comparing to unmodified samples and strongly dependent on the blend ratio and peroxide structure. The presented results confirmed that reactive blending supported by organic peroxide is a promising approach for tailoring novel biodegradable polymeric systems with controllable biodegradation rates.

Preparation, properties, and laser processing of poly(ɛ‐caprolactone)/poly(lactic acid) blends with addition of natural fibers as a potential for printing plates application

AbstractIn this research, biodegradable blend of poly(ɛ‐caprolactone) (PCL) and poly(lactic acid) (PLA) is proposed as a new material for the production of a printing plate for embossing process. Printing plates for embossing consist of raised printing elements and recessed nonimage elements. In production of printing plates, laser technology was used in order to form a relief printing plate. The embossing process is based on the principle of the pressure of the relief printing plate into the printing substrate, which causes the controlled deformation of the substrate and three‐dimensional (3D) effect. Coir fibers (CFs) were added as a natural filler to PCL/PLA blends to improve and adjust the properties of produced blends. Scanning electron microscopy micrographs, dynamic mechanical analysis analysis, roughness, and hardness were measured on prepared materials, and 2D and 3D microscopy was conducted on laser engraved printing plates. Results have shown that the addition of CFs improved the mechanical properties of produced materials. DMA results indicate the semicrystalline structure of all prepared blends, and that the addition of CFs raises the elasticity of the composites. Laser engraving showed that it is possible to engrave the produced biodegradable materials and to use it as a material for production of printing plates.

Preparation and Characterization of Functional Films Based on Chitosan and Corn Starch Incorporated Tea Polyphenols

The functional films based on chitosan and corn starch incorporated tea polyphenols were developed through mixing the chitosan and starch solution and the powder of tea polyphenols by the casting method. The objective of this research was to investigate the effect of different concentrations of tea polyphenols on the functional properties of the films. Attenuated total reflectance Fourier transform infrared spectrometry and X-ray diffraction were used to investigate the potential interactions among chitosan, corn starch and tea polyphenols in the blend films. Physical properties of the blend films, including density, moisture content, opacity, color, water solubility and water swelling, as well as morphological characteristics, were measured. The results demonstrated that the incorporation of tea polyphenols caused the blend films to lead to a darker appearance. The water solubility of the blend film increased with the increase of tea polyphenol concentrations, while moisture content and swelling degree decreased. The hydrogen bonding between chitosan, starch and tea polyphenols restricted the movement of molecular chains and was helpful to the stability of the blend films. The results suggested that these biodegradable blend films could potentially be used as packaging films for the food and drug industries to extend the shelf life to maintain their quality and safety.

Physico-Chemical, Mechanical and Morphological Properties of Biodegradable Films Based on Arrowroot Starch and Poly(vinyl alcohol)

Biodegradable polymeric blends have been widely studied due to their potential of reducing pollution caused by non-biodegradable materials. The research described here describes a polymer blend that benefits both from the abundance of arrowroot starch (AS) and the good mechanical properties of poly(vinyl alcohol) (PVA). Glycerol (GLY) was used in different proportions as a plasticizer. The addition of GLY improved the mechanical properties of the blends, increasing the elongation at break up to 667%. On the other hand, the GLY addition adversely affected other properties, increasing the water vapor permeability (WVP), solubility and hydrophilic characteristics and reducing the thermal stability and the crystallinity index. The AS/PVA blend without GLY addition showed better physical-chemical properties, having strong chemical interaction between the two kinds of polymeric chains (according FTIR analysis) and a homogeneous morphology (SEM morphological analysis). In general, decreasing the AS content improved the mechanical and WVP properties, the film becoming less hydrophilic. In conclusion, the AS/PVA blends cast films, with or without GLY, are biodegradable materials suitable for packaging applications.

Biodegradable blends of poly(butylene adipate‐co‐terephthalate) and polyglycolic acid with enhanced mechanical, rheological and barrier performances

AbstractBlends of poly(butylene adipate‐co‐terephthalate)/polyglycolic acid (PBAT/PGA) were prepared by melt blending, in which PGA was used as reinforcing component. Impacts of PGA content on tensile property, microstructure, crystallization property, melt viscosity, barrier performance of the blends were researched. Compared with very soft behavior of PBAT, the tensile yield strength and modulus of PBAT/PGA (65/35) sample increased from 7.67, 62.6 MPa of neat PBAT to 12.05, 158.9 MPa, respectively. However, owing to poor PBAT/PGA interface compatibility, its elongation at break decreased significantly from 1082.1% to 88.7%. An epoxy chain extender (ADR) was used as reactive modifier to improve its interface compatibility and rheological property. The related physical properties of PBAT/PGA/ADR (65/35/x) samples with various ADR contents were evaluated in detail. It was found that ADR exerted relatively complex influences on the properties. Overall, compared with neat PBAT and PBAT/PGA (65/35) sample, the PBAT/PGA/ADR (65/35/x) samples exhibited better stiffness‐ductility balance and higher processing stability.

Vibrational Spectroscopy Analysis of Oligothiophene Blend Film

One of the challenges in fabricating organic semiconductor thin film is to produce bettermolecular ordering that compromise its electronic properties. Molecular ordering of amorphous thin film can be improved in many ways. Here, high molecular weight polylactic acid (PLA) is introduced as binding matrix to promote 3'''-didodecyl-2,2':5',2'':5'',2'''-quaterthiophene (4T) film’s homogeinity across indium tin oxide (ITO) surface. Molecular ordering of the spin coated biodegradable PLA and 4T blend film processed at ambient atmosphere was studied using two vibrational spectroscopy methods. The complementary analysis of infrared absorption spectrum and Raman spectrum had identified several vibrational modes contributed by thiophene rings and alkyl functional groups. The Raman analysis implied there is a slight change of thiophene ringsʼ molecular orientation due to compressive stress after introduction of polymer. Microscopic characteristics of oligothiophenes especially at the π-π conjugated backbones contained crucial information in order to exploit the oligothiophene as flexible electronics devices.

Study of the Biodegradation of PLA/PBAT Films after Biodegradation Tests in Soil and the Aqueous Medium

The intense consumption of conventional plastics has been generating a series of problems for nature due to the accumulation of municipal solid waste because of its difficult degradation. Therefore, the use of biodegradable polymers becomes a good option to minimize these effects. Poly (lactide acid)/poly(butylene adipate-co-terephthalate) (PLA/PBAT) is a biodegradable blend that can be used mainly in applications that have a short shelf life. So, it is important to know the total biodegradation time of this blend. For this reason, PLA/PBAT films (1.5 x 1.5 x 0.15 cm) were produced by thermal compression molding to be subjected to biodegradation tests in soil and aqueous medium for 180 days. The films were characterized by visual analysis, weight loss measurements, differential scanning calorimetry (DSC), Fourier transforms infrared spectroscopy (FT-IR), contact angle, and scanning electron microscopy (SEM). DSC showed an increase of 0.7% in PLA crystallinity subjected to the aqueous medium, while FT-IR showed a reduction in the bands at 1710 cm-1 and 1100 cm-1, as a result of hydrolysis for both methodologies. The blend's hydrophilic character was increased after both degradation processes, presenting a reduction of 34.5% in the contact angle after biodegradation in soil. From the results, it was possible to conclude that PLA/PBAT films did not degrade completely, as expected, but showed signs that indicated the beginning of the degradation. The degradation was more effective in the aqueous medium.

Bilayered electrospun membranes composed of poly(lactic-acid)/natural rubber: A strategy against curcumin photodegradation for wound dressing application

Curcumin is a natural phenolic compound renowned for its beneficial anti-carcinogenic, anti-oxidant, antibacterial and anti-inflammatory properties. More recently, this active compound has also demonstrated wound healing capability and antibacterial properties, which are essential prerequisites to treat skin injuries. However, the practical application of curcumin in wound-healing dressing is limited by its susceptibility to photodegradation when exposed to artificial or natural sunlight. To maintain the pharmacological and antibacterial properties of curcumin and prevent its photodegradation, we have developed a bilayered asymmetric membrane for wound healing application composed of two layers of electrospun fibers. The bottom layer is composed of a biodegradable blend of poly(lactic acid)(PLA)/natural rubber(NR) microfibers containing curcumin in the bulk. In contrast, the top layer is composed solely of PLA nanofibers to simultaneously protect curcumin against photodegradation and avoid bacterial penetration. Scanning electron microscopy, Fourier transform infrared spectroscopy, UV–Vis spectroscopy, thermal analyses, contact angle measurements and antibacterial assay were employed to investigate the properties of the membranes. Our results demonstrated the top layer of PLA was crucial to prevent the photodegradation of curcumin contained in the PLA/NR microfibers bottom layer and also avoided the penetration of bacteria for 10 days. Additionally, the PLA/NR microfibers showed strong antibacterial activity against Staphylococcus aureus. Our results demonstrated the potential of bilayered nano/microfibrous membranes to be applied in the design of wound dressings containing active compounds susceptible to photodegradation.

Electrical Properties of Preparing Biodegradable Polymer Blends of PVA/Starch Doping with Rhodamine –B

This research focuses on the characteristics of polyvinyl alcohol and starch polymer blends doping with Rhodamine-B. The polymer blends were prepared using the solution cast method, which comprises 1:1(wt. /wt.). The polymer blends of PVA and starch with had different ratios of glycerin 0, 25, 30, 35, and 40 % wt. The ratio of 30% wt of glycerin was found to be the most suitable mechanical properties by strength and elasticity. The polymer blend of 1:1 wt ratios of starch/PVA and 30% wt of glycerin were doped with different ratios of Rhoda mine-B dye 0, 1, 2, 3, 4, 5, and 6% wt and the electrical properties of doping biodegradable blends were studied. The ratio of Rhodamine-B 5% wt to the polymer blends showed high conductivity up to 1×10-3. In general, the electrical conductivity was increased with high temperature, which is similar to the behavior of semi-conductive polymers. This work focuses on the characteristics of polymer blend based on starch and polyvinyl alcohol doping with Rhodamine-B. the polymer blends were prepared using the solution cast method, which comprising 1:1(wt./wt.). ratio starch and polyvinyl alcohol and different ratio of glycerin (0, 25, 30, 35,and 40) %. The ratio of 30% of glycerin was found to be the most suitable mechanical properties. The polymer blend of 1:1 starch/PVA and 30%of glycerin were doped with different ratio of Rhoda mine-B dye (0, 1, 2, 3, 4, 5, and 6%) and the electrical properties of doping biodegradable blends were studied. The ratio of Rhodamine-B 5% to the polymer blends was high conductivity up to 1×10-3. In general, the electrical conductivity was increased with high temperature this is similar to the behavior of semi-conductive polymers. This work focuses on the characteristics of polymer blend based on starch and polyvinyl alcohol doping with Rhodamine-B. the polymer blends were prepared using the solution cast method, which comprising 1:1(wt./wt.). ratio starch and polyvinyl alcohol and different ratio of glycerin (0, 25, 30, 35,and 40) %. The ratio of 30% of glycerin was found to be the most suitable mechanical properties. The polymer blend of 1:1 starch/PVA and 30%of glycerin were doped with different ratio of Rhoda mine-B dye (0, 1, 2, 3, 4, 5, and 6%) and the electrical properties of doping biodegradable blends were studied. The ratio of Rhodamine-B 5% to the polymer blends was high conductivity up to 1×10-3. In general, the electrical conductivity was increased with high temperature this is similar to the behavior of semi-conductive polymers.

Biodegradable Cationic Polymer Blends for Fabrication of Enhanced Artificial Antigen Presenting Cells to Treat Melanoma

Biomimetic biomaterials are being actively explored in the context of cancer immunotherapy because of their ability to directly engage the immune system to generate antitumor responses. Unlike cellular therapies, biomaterial-based immunotherapies can be precisely engineered to exhibit defined characteristics including biodegradability, physical size, and tuned surface presentation of immunomodulatory signals. In particular, modulating the interface between the biomaterial surface and the target biological cell is key to enabling biological functions. Synthetic artificial antigen presenting cells (aAPCs) are promising as a cancer immunotherapy but are limited in clinical translation by the requirement of ex vivo cell manipulation and adoptive transfer of antigen-specific CD8+ T cells. To move toward acellular aAPC technology for in vivo use, we combine poly(lactic-co-glycolic acid) (PLGA) and cationic poly(beta-amino-ester) (PBAE) to form a biodegradable blend based on the hypothesis that therapeutic aAPCs fabricated from a cationic blend may have improved functions. PLGA/PBAE aAPCs demonstrate enhanced surface interactions with antigen-specific CD8+ T cells that increase T cell activation and expansion ex vivo, associated with significantly increased conjugation efficiency of T cell stimulatory signals to the aAPCs. Critically, these PLGA/PBAE aAPCs also expand antigen-specific cytotoxic CD8+ T cells in vivo without the need of adoptive transfer. Treatment with PLGA/PBAE aAPCs in combination with checkpoint therapy decreases tumor growth and extends survival in a B16-F10 melanoma mouse model. These results demonstrate the potential of PLGA/PBAE aAPCs as a biocompatible, directly injectable acellular therapy for cancer immunotherapy.

Morphological and mechanical properties of biodegradable poly(glycolic acid)/poly(butylene adipate-co-terephthalate) blends with in situ compatibilization.

In the present work, the biodegradable blends of poly(glycolic acid) (PGA) and poly(butylene adipate-co-terephthalate) (PBAT) with in situ compatibilization using 4,4′-methylenebis(phenyl isocyanate) (MDI) were prepared. The combined results of FTIR, DSC, SEM, DSC, POM, TGA and rheology demonstrated that the MDI was successfully reacted with PGA/PBAT, the complex viscosity and storage moduli (G′) of the blends were increased. Melt elasticity and viscosity of the blends were also increased on increasing the concentration of PBAT. SEM results indicated that the compatibility was improved by in situ compatibilization. Due to the apparent differences in melting temperature (Tm) between PGA and PBAT, the morphology of the dispersed phase evolved from a spherical structure to in situ microfiber when the content of PBAT was up to 60% during injection molding. The interfacial adhesion between PGA and PBAT was strengthened, consequently, the impact strength of the blend was sharply increased from 9.0 kJ m−2 to 22.2 kJ m−2. On account of the chain extension effect, the crystallinity, crystallization temperature and crystallization size were decreased, which was also of benefit for the improvement of toughness. Meanwhile, the thermal stability of the PGA was improved through blending with PBAT. A novel biodegradable blending material with enhanced toughness and thermal stability was prepared.

Study of mechanical properties behaviour of biodegradable blends based on wood adhesive, lactic acid, polyvinyl alcohol, and aloe Vera

Abstract In this work, polymer blends of PVA and wood Adhesive with aloe Vera gel as antibacterial (germs-killing) were prepared by pouring the solvent and bonded with lactic acid to improve its properties. Mechanical properties were examined closely with the presence of aloe Vera gel and lactic acid into PVA /wood Adhesive polymer blends, while the lactic acid crosslinking promoted the formation of good polymer blends with anew behavior in comparison to those of the polymer blends without lactic acid and aloe Vera gel. The worth the mechanical properties of (PVA/wood adhesive) blends measured the elongation, Young’s modulus, and stress–strain have good mechanical properties of these polymer blends can be used for many applications such as packaging, wound healing, and drug delivery applications.

Properties and Degradation of Novel Fully Biodegradable PLA/PHB Blends Filled with Keratin.

The utilization of keratin waste in new materials formulations can prevent its environmental disposal problem. Here, novel composites based on biodegradable blends consisting of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate) (PHB), and filled with hydrolyzed keratin with loading from 1 to 20 wt % were prepared and their properties were investigated. Mechanical and viscoelastic properties were characterized by tensile test, dynamic mechanical thermal analysis (DMTA) and rheology measurements. The addition of acetyltributyl citrate (ATBC) significantly affected the mechanical properties of the materials. It was found that the filled PLA/PHB/ATBC composite at the highest keratin loading exhibited similar shear moduli compared to the un-plasticized blend as a result of the much stronger interactions between the keratin and polymer matrix compared to composites with lower keratin content. The differences in dynamic moduli for PLA/PHB/ATBC blend filled with keratin depended extensively on the keratin content while loss the factor values progressively decreased with keratin loading. Softening interactions between the keratin and polymer matrix resulted in lower glass transitions temperature and reduced polymer chain mobility. The addition of keratin did not affect the extent of degradation of the PLA/PHB blend during melt blending. Fast hydrolysis at 60 °C was observed for composites with all keratin loadings. The developed keratin-based composites possess properties comparable to commonly used thermoplastics applicable for example as packaging materials.

Preparation physical, mechanical properties and biodegradable study of SAN/EOC/nanoclay/proteins nanocomposite

In this paper, the mechanical and morphological properties of biodegradable SAN/EOC/Nanoclay/Proteins nanocomposite were investigated. The composites were first prepared by a laboratory-scale twin screw extruder. Morphology of the blend was determined by SEM images. Mechanical properties in terms of tensile tests were carried out by Testometric TS2000, stress at break, strain at break, and Young’s modulus was determined. Based on mechanical results, although the young’s modulus increases with increasing protein content but the strain at break of the composite decreases acutely because of the presence of protein. The blend indicated an improvement in mechanical and thermal properties. Today, according to the vast application of plastic in different fields, environmental issues were affected by these kinds of non-degradable materials, so that biodegradability of the plastics is just the remaining route to solve. In this research, biodegradable blends were prepared using whey protein as a biodegradable natural polymer. The results of the biological procedure-test after 3 months indicated sufficient weight loss and biodegradation of these blends.

Printability, Mechanical and Thermal Properties of Poly(3-Hydroxybutyrate)-Poly(Lactic Acid)-Plasticizer Blends for Three-Dimensional (3D) Printing.

This paper investigates the effect of plasticizer structure on especially the printability and mechanical and thermal properties of poly(3-hydroxybutyrate)-poly(lactic acid)-plasticizer biodegradable blends. Three plasticizers, acetyl tris(2-ethylhexyl) citrate, tris(2-ethylhexyl) citrate, and poly(ethylene glycol)bis(2-ethylhexanoate), were first checked whether they were miscible with poly(3-hydroxybutyrate)-poly(lactic acid) (PHB-PLA) blends using a kneading machine. PHB-PLA-plasticizer blends of 60-25-15 (wt.%) were then prepared using a corotating meshing twin-screw extruder, and a single screw extruder was used for filament preparation for further three-dimensional (3D) fused deposition modeling (FDM) printing. These innovative eco-friendly PHB-PLA-plasticizer blends were created with a majority of PHB, and therefore, poor mechanical properties and thermal properties of neat PHB-PLA blends were improved by adding appropriate plasticizer. The plasticizer also influences the printability of blends, which was investigated, based on our new specific printability tests developed for the optimization of printing conditions (especially printing temperature). Three-dimensional printed test samples were used for heat deflection temperature measurements and Charpy and tensile-impact tests. Plasticizer migration was also investigated. The macrostructure of 3D printed samples was observed using an optical microscope to check the printing quality and printing conditions. Tensile tests of 3D printed samples (dogbones), as well as extruded filaments, showed that measured elongation at break raised, from 21% for non-plasticized PHB-PLA reference blends to 84% for some plasticized blends in the form of filaments and from 10% (reference) to 32% for plasticized blends in the form of printed dogbones. Measurements of thermal properties (using modulated differential scanning calorimetry and oscillation rheometry) also confirmed the plasticizing effect on blends. The thermal and mechanical properties of PHB-PLA blends were improved by the addition of appropriate plasticizer. In contrast, the printability of the PHB-PLA reference seems to be slightly better than the printability of the plasticized blends.

Recycling possibilities of bioplastics based on PLA/PHB blends

The study is focused on modelling the evaluation of recyclability of the biodegradable blend using multiple extrusion of selected composition of PLA/PHB blend which had been more deeply studied before. It was shown that the multiple extrusion reduces viscosity of the tested blend due to multiple thermomechanical stresses and the material was partially degraded. Partial degradation was demonstrated by measuring of molecular characteristics. The degree of degradation of the tested material was determined with relatively high accuracy after creating a colour space/viscosity. Multiple processing and subsequent degradation of the tested material did not negatively affect thermal properties, as well as strength characteristics of the blend. It was concluded that the biodegradable polymer blend of the PLA/PHB type is suitable for multiple processing and material recycling can be applied for this type of bioplastics.