Biodegradable Polymer Blends Research Articles

Study on structure and properties of biodegradable PLA/PBAT/organic-modified MMT nanocomposites

Biodegradable polymer blends were prepared by melt blending poly(lactic acid) (PLA), poly(butylene adipate- co-terephthalate) (PBAT), and organic-modified montmorillonite (MMT). The effects of MMT on the structure, morphology, thermal, and mechanical properties of the blends were thoroughly investigated. The results revealed that MMT was preferable to localize on the interface of PLA and PBAT and esterification reaction took place between organic-modified MMT and PLA/PBAT. MMT enhanced the compatibility of PLA and PBAT, accelerated crystallization, and improved the thermal stability of PLA and PBAT. In addition, MMT illustrated the reinforcing effects on PLA and PBAT in their tensile strength, especially for PBAT.

Testing and characterization of binary and ternary blends with poly (lactic acid), acrylonitrile-butadiene-styrene and tapioca cassava starch powder

In this research paper explores about biodegradable polymers such as Poly lactic acid (PLA), Acrylonitrile-Butadiene-Styrene (ABS) and Tapioca cassava starch powder (TCSP) and their blends prepared using conventional method. The prepared bio degradable polymer blends are analyzed with the help of Universal testing machine (UTM-3969), scanning electron microscopy (SEM).On the weight basis PLA, ABS, and TCSP are transferred into binary and ternary blends such as PLA, ABS, PLA/ABS, PLA/ABS/TCSP (wt.%) etc. are compared with various mechanical properties such as tensile stress v/s tensile strain, tensile strength v/s tensile module and compressive. The scanning electron microscopy images for tensile fractured samples showed smooth homogeneous finish and good partial distribution.

Characterization of the Effect of Clay on Morphological Evaluations of PLA/Biodegradable Polymer Blends by FT-Rheology

The effects of Cloisite nanoparticulate clays on the morphologies of three biodegradable polymer blends, that is, poly(lactic acid) (PLA)/poly(e-caprolactone) (PCL), PLA/poly(butylene adipate-co-te...

Photo-Oxidative and Soil Burial Degradation of Irrigation Tubes Based on Biodegradable Polymer Blends.

Irrigation tubes based on biodegradable polymers were prepared via an extrusion-drawing process by Irritec and compared to conventional pipes made of high-density polyethylene (HDPE). A commercial polylactide/poly (butyleneadipate-co-butyleneterephthalate) (PLA/PBAT) blend (Bio-Flex®) and Mater-Bi® were used. The polymers were characterized from rheological and mechanical points of view. Irrigation pipes were subjected to photoaging with continued exposure to UV radiation up to 22 days. The degradability in the soil of irrigation tube samples was studied. The influence of temperature and UV irradiation on soil burial degradation was investigated. A soil burial degradation test was carried out at 30 °C and 50 °C for up to 70 days. The degree of degradation was evaluated from the weight loss percentage. The degradation rate of irrigation tube samples based on Mater-Bi® was higher at 30 °C and was stimulated after 14 days of UV irradiation. Higher temperatures or UV aging encouraged the disintegration in soil of Bio-Flex®-based irrigation tubes. Furthermore, tube samples, before and after UV and soil burial degradation, were analyzed by Attenuated Total Reflection-Fourier Transform Infra-Red (ATR-FTIR) spectroscopy.

Cold Crystallization Temperature Correlated Phase Separation, Performance, and Stability of Polymer Solar Cells

Summary Fabrication of non-fullerene (NF)-based polymer solar cells (PSCs) has been an arduous task involving various approaches to optimize the morphology of blend film for superior performance. In this work, unique exothermic peaks can be observed in differential scanning calorimetry first heating scan of the blend films, which are assigned to the cold crystallization temperature (TCC) of NF acceptors when blended with different degree of crystallinity polymers, and TCC contains the phase information at quenched stage of the film development. A linear correlation between the phase separation parameters and TCC was established, which helps to select the appropriate donor for a specific acceptor. Utilizing multiple polymer-NF blend systems, we report an expectation TCC value between 210°C and 230°C, which would promise balanced domain size, purity, and consequentially superior performance. Further investigation revealed that TCC can also be used to evaluate the thermal stability.

Morphological, thermal, rheological and mechanical properties of poly (butylene carbonate) reinforced by stereocomplex polylactide

Fully biodegradable blends of poly (butylene carbonate) (PBC) and a bioresource-based stereocomplex polylactide (sc-PLA) were prepared by melt compounding at a temperature far below the melting point (Tm) of sc-PLA, and above the Tm of PBC, poly (l-lactide) (PLLA) and poly(d-lactide) (PDLA). sc-PLA was uniformly dispersed in the PBC matrix as spherical particles. Interestingly, the size of the dispersed sc-PLA particles did not increase significantly with increasing amounts of PLLA and PDLA. sc-PLA accelerated the non-isothermal and isothermal melt crystallization of PBC. Simultaneously, the thermal decomposition temperature of the PBC/sc-PLA blends increased by about 46 °C. The solid filler sc-PLA could reinforce the PBC matrix over a relatively wide temperature range. Consequently, formation of the percolation network structure of spherical sc-PLA in the blends significantly improved the rheological and mechanical properties of PBC after incorporation of sc-PLA. This report may open a new avenue to achieve higher-performance biodegradable polymer blend materials.

Compatibilization of immiscible PLA-based biodegradable polymer blends using amphiphilic di-block copolymers

Block copolymer is an effective compatibilizer for PLA-based biodegradable polyester blends to improve the mechanical properties. However, how to find an “A-C” type of di-block copolymer as a common compatibilizer for improving the miscibility of A and B blends is very challenging. In this research, monomethoxy poly(ethylene glycol)-polylactide (MPEG-PLA) di-block copolymers were synthesized for compatibilization of PLA-based polyester blends, such as PLA with poly(butylene adipate-co-terephthalate) (PBAT), or poly(butylene succinate) (PBS), or poly(butylene succinate-co-adipate) (PBSA). The results showed that the di-block successfully reduced the interfacial tension and improved the interfacial adhesion, thereby, the size of dispersed phase decreased from 2 μm to 0.3 μm with the addition of MPEG-PLA copolymer which the segment ratio of EG/LA was 2.5 in PLA/PBAT blends. Moreover the elongation at the break of the blends was as high as 296%, which was ten times more than the pristine blends. Furthermore the MPEG-PLA di-block copolymer with specific structure improved the mechanical properties and changed the phase morphology of PLA/PBS and PLA/PBSA blends. In the blends, PEG segment in “A-C” di-block copolymer acted as B blocks in “A-B” di-block copolymers to improve the compatibility of PLA-based biodegradable polymer blends.

Novel tunable super-tough materials from biodegradable polymer blends: nano-structuring through reactive extrusion.

Structuring blends on sub-micrometer scales, especially nano-scales, has a higher potential for improving their thermomechanical properties. Here, we propose a design strategy to fabricate compatible nano-blends by manipulating the reactions between two biodegradable polymers, e.g. polybutylene succinate (PBS) and polybutylene adipate terephthalate (PBAT), with extremely low free radical contents through reactive extrusion processing. Observed by transmission electron microscopy (TEM) and atomic force microscopy (AFM), it is found that PBAT is tightly surrounded by large amounts of PBS–PBAT co-polymers and dispersed in a PBS matrix with a particle size of less than 100 nm. We show how impact strength and polymer moduli can be improved simultaneously by decreasing the small amount of dispersed phase into nano-scale (droplet or lamina structures). With 5 wt% PBAT content in the PBS–PBAT blend, the notched impact strength of PBS is increased 1200% and the Young's modulus is increased 15%. Through in situ rheological monitoring and Fourier-transform infrared spectroscopy (FTIR) studies, the reason why nano-blends can be formed in such a low amount of peroxide is illustrated. Our investigation most significantly indicates the transformation of the partially compatible PBS–PBAT micro-blend into a fully compatible PBS–PBAT through nano-structuring. This work addresses the importance of reaction rate and mechanism in favoring the formation of co-polymers rather than homo-polymer crosslinking or self-decomposition in polymer blend modification via reactive extrusion design.

Investigation on the Electrical Properties of Lithium Ion Conducting Polymer Electrolyte Films Based on Biodegradable Polymer Blends

In the present work, the polyvinyl alcohol/poly (N-vinyl pyrrolidone)/Lithium carbonate (PVA/PVP/Li2CO3) blend polymer electrolyte films were prepared via the solution casting technique, with varying concentration of Li2CO3 salt (0 to 25 wt%). The surface morphology of these blend electrolyte films was examined using polarized optical microscopy (POM). The electrical properties such as impedance (Z), quality factor (Q-factor) and phase angle () of PVA/PVP/Li2CO3 blend electrolyte films were elucidated using impedance analyzer in the frequencies from 50 Hz to 20 MHz and temperatures from 30 °C to 150 °C. It was observed that the inclusion of Li2CO3 salt into the PVA/PVP blend matrix led to an increase in the Z,  and Q-factor values. The maximum Z of 1.19 x 107 Ω (50 Hz, 30 °C) was observed for blend electrolyte film containing 25 wt% Li2CO3 salt. The  also increased from 139° (20 MHz, 90 °C) for PVA/PVP blend to 179° (20 MHz, 40 °C) for blend electrolyte film containing 25 wt% Li2CO3 salt. The Q-factor values was increased from 27.4 (10 MHz, 140 °C) for PVA/PVP blend to 56.2 (5 MHz,salt, 80 °C) for blend electrolyte film containing 25 wt% Li2CO3 salt.

Cold crystallization kinetics of biodegradable polymer blend; controlled by reactive interactable and nano nucleating agent

Poly(lactic acid) (PLA) is famous for its crystalline nature and ability to show exothermic crystallization (cold crystallization) peak during heating cycle of differential scanning calorimetric study. To get an insight into the mechanism of cold crystallization of PLA in its promising forms like biodegradable blend and biodegradable blend nanocomposite, a kinetic study has conducted and reported in the present study. Biodegradable blend of PLA has prepared with poly(hydroxybutyrate) (PHB). Subsequently, blend nanocomposite has prepared using organically modified layered nano silicate. Maleic anhydride has used as a reactive compatibilization agent to modify the interface of the partially miscible blend of PLA and PHB. Kinetics and mechanism of crystallization have monitored through isothermal cold crystallization method on the basis of Avrami relationship. Avrami exponent ‘n’ and equilibrium rate constant ‘K’ value has taken into consideration to quantify the crystallization rate. The half-life of crystallization and equilibrium melting point also has estimated as additional findings to confirm the estimated rate of crystallization. Variation in the energy of activation (Ea) using Arrhenius relation and regime transitions during crystallization process through Lauritzen–Hoffman (L-H) equation also have been reported.

Optimising Ductility of Poly(Lactic Acid)/Poly(Butylene Adipate-co-Terephthalate) Blends Through Co-continuous Phase Morphology

This paper examines the effect of the melt viscosities of the two component polymers on the morphology and mechanical properties of a series of biodegradable polymer blends. Melt blended compounds of poly(lactic acid) (PLA) and poly(butylene adipate-co-terephthalate) (PBAT) are prepared and their melt viscosities, thermal properties, crystallinity, mechanical properties and phase morphology are investigated. From the relative melt viscosities of PLA and PBAT in the processing regime used in the study, it is possible to calculate the volume fraction at which a co-continuous phase structure is formed. The predicted value is 19 wt% of PBAT and this value is verified by the results of mechanical properties, where results for elongation-to-break show a dramatic rise from around 10% up to 300% in the composition range between 10 and 20 wt% of PBAT. The co-continuous phase structure is also validated by scanning electron microscopy.Graphical

Assimilation of NH₄Br in Polyvinyl Alcohol/Poly(N-vinyl pyrrolidone) Polymer Blend-Based Electrolyte and Its Effect on Ionic Conductivity.

Biodegradable polymer blend electrolyte based on ammonium based salt in variation composition consisting of PVA:PVP were prepared by using solution casting technique. The obtained films have been analyzed by various technical methods like as XRD, FT-IR, TG-DSC, SEM analysis and impedance spectroscopy. The XRD and FT-IR analysis exposed the amorphous nature and structural properties of the complex formation between PVA/PVP/NH4Br. Impedance spectroscopy analysis revealed the ionic conductivity and the dielectric properties of PVA/PVP/NH4Br polymer blend electrolyte films. The maximum ionic conductivity was determined to be 6.14 × 10-5 Scm-1 for the composition of 50%PVA: 50%PVP: 10% NH4Br with low activation energy 0.3457 eV at room temperature. Solid state battery is fabricated using highest ionic conducting polymer blend as electrolyte with the configuration Zn/ZnSO4 · 7H2O (anode) ∥ 50%PVA: 50%PVP: 10% NH4Br ∥ Mn2O3 (cathode). The observed open circuit voltage is 1.2 V and its performance has been studied.

Electrospinning polymer blend of PLA and PBAT: Electrospinnability–solubility map and effect of polymer solution parameters toward application as antibiotic‐carrier mats

ABSTRACTElectrospinning of a biodegradable polymer blend of poly(lactic acid) (PLA) and poly(butylene adipate‐co‐terephthalate) (PBAT) is reported for the first time. Effects of several solution parameters on electrospinning are explored, including types of single and binary solvents, binary solvent mixing ratio, polymer blend concentration, polymer blending ratio, and loading content of tetrabutyl titanate as a compatibilizer. An electrospinnability–solubility map of the PLA/PBAT blend is firstly developed for the facile selection of a suitable binary solvent system, thus simplifying the laborious, time‐consuming, trial‐and‐error process. A particular binary solvent system derived from good and non‐solvent serves as the most suitable medium for the successful preparation of homogeneous bead‐free electrospun PLA/PBAT nanofibers. It is revealed that the compatibilizer acts not only as a diameter size tuner for the PLA/PBAT fibers but also as a mechanical property enhancer for the immiscible PLA/PBAT electrospun mats. Moreover, the antibacterial activity of the drug‐loaded PLA/PBAT fibrous mats suggests their potential application as antibiotic‐carrier mats. Preparation of the composite mats comprising bead‐free fibers with an average size at sub‐micrometer scale is also demonstrated, additionally promoting the possibility of using the PLA/PBAT‐based electrospun mats as a matrix of various additives for a wide range of applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46486.

Influence of high molecular weight poly(ethylene adipate) on the crystallization behavior and mechanical properties of biodegradable poly(l-lactide) in their immiscible polymer blend

A fully biodegradable polymer blend consisting of poly(l-lactide) (PLLA) and poly(ethylene adipate) (PEA) with relatively high number average molecular weight of 8000 g/mol (80/20 in weight ratio) was prepared through a solution and casting method. The dynamic mechanical analysis and scanning electron microscopy studies confirmed that PLLA was immiscible with PEA. The crystallization behavior, crystal structure and mechanical properties of PLLA/PEA blend were investigated and compared with those of neat PLLA. In the immiscible blend, the blending with PEA enhanced the nonisothermal cold and melt crystallization behavior, decreased the isothermal melt crystallization rate and retained the crystallization mechanism and crystal structure of PLLA. The tensile test results revealed that the ductility and toughness of PLLA phase were significantly improved by the blending with high molecular weight PEA.

Preparation and property testing of polymer blends of poly(lactic acid) and poly(butylene succinate) plasticised with long-chain fatty acids

ABSTRACTThis study investigates the influence of three fatty acids (lauric acid, palmitic acid, and stearic acid) on biodegradable polymer blends based on poly(lactic acid) (PLA) and poly(butylene succinate) (PBS), containing different weight ratios (100:0, 100:2, and 100:4) of fatty acids on the transparency, mechanical properties, morphology, contact angle, and water vapour permeability. All of the blends were pressed into thin films and tested. The experimental results showed that the properties of the samples varied with chain length and amounts of the fatty acids. Thus, it could be concluded that use of fatty acids opens up new ways for the plasticisation of PLA/PBS blends for use as new bioplastics.

Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends

This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), instead, the responsivity increases up to 220 μA/MPa in terms of ΔI/ΔP (i.e. (ΔI/ΔI0)/P close to 1 kPa−1). Furthermore, this novel sensor is able to monitor submicrometric displacements with an impressive sensitivity (up to 25 μA/μm in terms of ΔI/ΔL, or 70 in terms of (ΔI/I0)/ε). We implemented a model able to predict pressure changes up to 25 MPa, by monitoring and measuring variations in electrical conductivity, thus paving the road to use these biodegradable, ecofriendly materials as low-cost sensors for a large pressure range.

Reactive extrusion of bio-based polymer blends and composites – Current trends and future developments

Reactive extrusion is a cost-effective and environmentally-friendly method to produce new materials with enhanced performance properties. At present, reactive extrusion allows in-situ polymerization, modification/functionalization of polymers or chemical bonding of two (or more) immiscible phases, which can be carried out on commonly used extrusion lines. Although reactive extrusion has been known for many years, its application for processing of bio-based polymer blends and composites is a relatively new direction of scientific research. This work presents a literature review on recent advances in the processing of bio-based polymer blends and composites via reactive extrusion. We described compatibilization mechanisms for different types of biodegradable polymeric materials based on: (i) aliphatic polyesters, (ii) aliphatic polyesters/starch and (iii) aliphatic polyester/natural rubber systems. A special attention was focused on conventional and dynamic cross-linking of bio-based polymer blends and composites as an effective way to prepare new materials with unique properties e.g. biodegradable thermoplastic elastomers or shape-memory materials. Advantages and limitations affecting future trends in development of biodegradable polymer blends and composites reactive extrusion are also discussed.

Manufacturing and Characterization of Toughened Poly(lactic acid) (PLA) Formulations by Ternary Blends with Biopolyesters.

Ternary blends with a constant poly(lactic acid) (PLA) content (60 wt %) and varying amounts of poly(3-hydroxybutyrate) (PHB) and poly(ε-caprolactone) (PCL) were manufactured by one step melt blending process followed by injection moulding, with the main aim of improving the low intrinsic toughness of PLA. Mechanical properties were obtained from tensile and Charpy impact tests. The miscibility and morphology of the system was studied by thermal analysis and field emission scanning electron microscopy (FESEM). The obtained results showed a clear phase separation, thus indicating poor miscibility between these three biopolyesters, i.e., PLA, the continuous component with dispersed PHB and PCL domains in the form of different sphere size. Nevertheless, the high fragility of PLA was remarkably reduced, as detected by the Charpy impact test. In accordance with the decrease in brittleness, a remarkable increase in elongation at break is achieved, with increasing PCL load due to its flexibility; in addition, increasing PCL load provides thermal stability at high temperatures. Thus, tailored materials can be manufactured by melt blending PLA, PHB, and PCL in different percentages to offer a wide range of biodegradable polymer blends.

Effect of influent pH on biological denitrification using biodegradable PHBV/PLA blends as electron donor

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate)/poly (lactic acid) (PHBV/PLA), a biodegradable polymer blend, was used as both carbon source and biofilm carrier in a packed-bed bioreactor. The effect of influent pH on denitrification performance in PHBV/PLA supported denitrification system was further investigated. Results showed that the nitrate removal efficiency kept high level under an alkaline influent while largely decreased under an acidic influent. When the influent pH was 5.68, nitrate removal efficiency was about 34% of that on neutral or alkaline conditions. Meanwhile, dissimilatory nitrate reduction to ammonia process (DNRA) was enhanced on acidic condition. Furthermore, ΔpH (the difference between influent and effluent pH) and effluent TOC both increased on alkaline condition, and they sharply rose to 2.75 and 23.37 mg L−1 with an influent pH of 10.38. It was found that there were obvious positive correlations among influent pH, ΔpH and TOC. Moreover, based on the characteristics of microbial hydrolysis and denitrification processes, the effect mechanism of influent pH on nitrate removal was deeply explored. A better knowledge of the effect of influent pH on nitrate removal will be significant for the solid-phase denitrification in practice.

Biodegradable compatibilized polymer blends for packaging applications: A literature review

ABSTRACTThe majority of materials used for short‐term and disposable packaging application are non‐biodegradable which are not satisfying the demands in environmental safety and sustainability. Biodegradable polymers are an alternative for these non‐biodegradable materials. The biodegradable polymeric materials can degrade in a reasonable time period without causing environmental problems. However, biodegradable polymers possess some limitations such as comparatively high cost, insufficient mechanical performances, and inferior thermal stability to extend their widespread application in packaging industry. To overcome these limitations, one of the most commonly used strategies is melt blending of dissimilar biodegradable polymers. Unfortunately, most of the biodegradable polymer blends exhibit insufficient performance because they are thermodynamically immiscible as well as exhibit poor compatibility between the blended components. It has been established that the compatibilization is a well‐known strategy to improve the performances of the immiscible biodegradable polymer blends by enhancing the adhesion between the phases. As a result, recent studies focus on various compatibilizers to enhance the performances of the resulting biodegradable polymer blends. This review summarizes the recent developments on a variety of biodegradable polymer blends compatibilized by melt processing with a main focus of ex situ and in situ compatibilization strategies. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45726.