Poly Butylene Adipate Co-terephthalate Research Articles

Ylang-ylang (Cananga odorata) essential oils with flora odorants enhanced active function of biodegradable polyester films produced by extrusion

Ylang-ylang (Cananga odorata) essential oils (EO) has several active components with flora odorants which are compatible with several foods and desserts. Incorporation of Ylang-ylang EO into biodegradable polymers potentially produce functional packaging, releasing desirable aroma which is attractive to consumers. This research aimed to enhance active function of biodegradable polyester blend films namely polybutylene adipate-co-terephthalate (PBAT) and polybutylene succinate (PBS) using cast extrusion with Ylang-ylang EO. Characterizations of the film include morphology, relaxation, infrared absorption and packaging properties. Adding EO gave a smoother microstructure and surface topography and modified the crystal lattice of the PBS phase. Infrared absorption indicated EO-polymer interaction involving C–H stretching vibration. Polymer relaxation influenced transport of gas molecules through PBAT/PBS/EO matrices. Decreased α-relaxation temperature suggested plasticization effects of the amorphous PBAT phase by EO, increasing oxygen and water vapor permeability by 2.52 and 1.16 times, respectively. Polymer relaxation and crystallinity influenced transport of non-polar oxygen through PBAT/PBS/EO matrices. Moreover, films containing EO effectively delayed fungal growth in pandan pudding and layered pudding by more than 3 days due to the release of volatiles that exhibited antifungal activities. Findings suggested potential of Ylang-ylang EO incorporated biodegradable films to produce active packaging for aroma release, extending product shelf-life.

Polyesters Incorporating Gallic Acid as Oxygen Scavenger in Biodegradable Packaging.

Biodegradable polyesters polybutylene succinate (PBS) and polybutylene adipate-co-terephthalate (PBAT) were blended with gallic acid (GA) via cast extrusion to produce oxygen scavenging polymers. The effects of polyesters and GA contents (5 to 15%) on polymer/package properties were investigated. Increasing GA formed non-homogeneous microstructures and surface roughness due to immiscibility. GA had favorable interaction with PBAT than PBS, giving more homogeneous microstructures, reduced mechanical relaxation temperature, and modified X-ray diffraction and crystalline morphology of PBAT polymers. Non-homogenous dispersion of GA reduced mechanical properties and increased water vapor and oxygen permeability by two and seven folds, respectively. Increasing amounts of GA and higher humidity enhanced oxygen absorption capacity, which also depended on the dispersion characteristics of GA in the matrices. PBAT gave higher oxygen absorption than PBS due to better dispersion and higher reactive surface area. GA blended with PBAT and PBS increased oxygen scavenging activity as sustainable active food packaging using functional biodegradable polymers.

Design of interconnected 1D nanomaterials with selective localization in biodegradable binary thermoplastic nanocomposite films for effective electromagnetic interference shielding effectiveness

AbstractFlexible and electrically conductive polymer nanocomposite materials are gaining popularity as EMI shield materials. Herein, we report the successful fabrication of Thermoplastic polyurethane (TPU)/polybutylene adipate‐co‐terephthalate (PBAT)/dodecyl amine modified multi‐walled carbon nanotubes (MWCNT)‐based biodegradable polymer nanocomposite films employing solvent mixing and casting technique. The FESEM analysis of the cryofractured TPU/PBAT blend (containing 50 wt% of both the polymers) is found to be perfectly co‐continuous. Field emission scanning electron microscopy (FESEM), High‐resolution transmission electron microscopy (HRTEM) analysis followed by a selective dissolution test of polymer nanocomposites revealed that MAm nanofillers are mostly confined to the PBAT phase. The electrical percolation threshold is found to be between 3 and 5 wt% of dodecyl amine modified MWCNT loading as the electrical conductivity and EMI shielding efficiency are found to be shifting from 10−4 to 0.827 S/cm and −29.4 and −36 dB respectively as the nanofiller loading is increased from 3 to 5 wt% keeping the thickness of the polymer nanocomposite films constant at 0.8 mm.

Fabrication of a Polybutylene Succinate (PBS)/Polybutylene Adipate-Co-Terephthalate (PBAT)-Based Hybrid System Reinforced with Lignin and Zinc Nanoparticles for Potential Biomedical Applications.

Polybutylene adipate-co-terephthalate (PBAT) was used in an effort to improve the properties of polybutylene succinate (PBS). The resultant blend consisting of PBS/PBAT (70/30) was reinforced with lignin at different loadings (5 to 15 wt.%) and zinc (ZnO) nanoparticles (1.5 wt.%). Hot melt extrusion and injection moulding were used to prepare the hybrid composites. The mechanical, thermal, physical, self-cleaning, and antimicrobial properties of the resultant hybrid composites were investigated. The transmission electron microscopy (TEM) results confirmed that ZnO was successfully prepared with average diameters of 80 nm. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) confirmed that there were interactions between the fillers and the blend. The tensile strength and elongation at the break of the resultant materials decreased with increasing the loadings, while the tensile modulus showed the opposite trend. The melting behaviour of the blend was practically unaffected by incorporating lignin and ZnO nanoparticles. In addition, the incorporation of fillers reduced the thermal stability of the materials. Furthermore, the incorporation of ZnO nanoparticles introduced photocatalytic properties into the polymer blend, rendering it to be a functional self-cleaning material and enhancing its antimicrobial activities.

Shape memory property of polybutylene adipate-co-terephthalate

PurposeThe purpose of this study is to investigate the thermomechanical condition on the shape memory property of Polybutylene adipate-co-terephthalate (PBAT). PBAT is a widely researched and rapidly developed biodegradable copolyester. In a tensile test, we found that the fractured PBAT samples had a heat-driven shape memory effect which piqued our interest, and it will lay a foundation for the application of PBAT in new fields (such as heat shrinkable film).Design/methodology/approachThe shape memory effect of PBAT and the effect of the thermomechanical condition on its shape memory property were confirmed and systematically investigated by a thermal mechanical analyzer and tensile machine.FindingsThe results showed that the PBAT film had broad shape memory transform temperature and exhibited excellent thermomechanical stability and shape memory properties. The shape memory fixity ratio (Rf) of the PBAT films was increased with the prestrain temperature and prestrain, where the highest Rf exceeded 90%. The shape memory recovery ratio (Rr) of the PBAT films was increased with the shape memory recovery temperature and decreased with the prestrain value, and the highest Rr was almost 100%. Moreover, the PBAT films had high shape memory recovery stress which increased with the prestrain value and decreased with the prestrain temperature, and the highest shape memory recovery stress can reach 7.73 MPa.Research limitations/implicationsThe results showed that PBAT had a broad shape memory transform temperature, exhibited excellent thermomechanical stability and shape memory performance, especially for the sample programmed at high temperature and had a larger prestrian, which will provide a reference for the design, processing and application of PBAT-based heat shrinkable film and smart materials.Originality/valueThis study confirmed and systematically investigated the shape memory effect of PBAT and the effect of the thermomechanical condition on the shape memory property of PBAT.

Ecofriendly bioactive film doped CuO nanoparticles based biopolymers and reinforced by enzymatically modified nanocellulose fibers for active packaging applications

The objective of the current work was to prepare the active packaging bioactive films based on biodegradable Poly(butylene adipate-co-terephthalate (PBAT) containing copper oxide nanoparticles (CuO-NPs) by 2% and various loadings of enzymatically prepared nanocellulose fibers (ENC) to improve the bioactive film mechanical properties. The fabricated Poly(butylene adipate-co-terephthalate, nanocellulose fibers and copper oxide nanoparticles formula (PBAT/ENC@CuO-NPs) bioactive films were evaluated using ATR-FTIR, XRD, TEM, SEM and TGA mechanical properties. Moreover, the oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) of the attained PBAT/ENC@CuO-NPs bioactive films were assessed. The fabricated bioactive films exhibited good thermal stability as well as superior antimicrobial activity contrary to Gram-positive & Gram-negative bacteria, unicellular fungus and filamentous fungus. The obtained results displayed that the incorporation of ENC and dispersion of CuO-NPs in the PBAT matrix enhanced the biodegradation and the antimicrobial activities as well as the mechanical properties. The present study offers very promising materials for sustainable PBAT-based biodegradable and antimicrobial films for prospective applications in food packaging applications.

Biodegradable microplastic increases CO2 emission and alters microbial biomass and bacterial community composition in different soil types

Plastic input to the terrestrial environment is of global concern and the still increasing production and release worldwide reinforces this problem. It has been shown that microplastics (MPs) can affect soil structure and soil organisms, possibly leading to an increase in soil carbon turnover, microbial activity and resulting CO2 emissions. Yet, the response of soil CO2 emissions to various types, quantities, and sizes of microplastic is not well understood. The aim of this work was to investigate the effect of conventional and biodegradable microplastics on soil microbial biomass, bacterial community composition and CO2 development. Two types of plastics, LDPE (low-density polyethylene) and PBAT (polybutylene adipate-co-terephthalate), at low (0.1 %) and high (1 %) concentrations and in three different size ranges (50–200 μm, 200–500 μm, and 0.63–1.2 mm) were amended to a sandy loam and a loamy soil and CO2 emissions were measured over four weeks. Afterwards, microbial biomass and growth were estimated, and prokaryotic community shifts were inferred by amplicon sequencing. No effect of LDPE on soil CO2 emissions could be detected, but higher CO2 emissions (13–57 %), microbial biomass (1–7 %), and a shift in community composition was induced by addition of the biodegradable PBAT when added at high concentration. Soil CO2 emissions were 10–13 % greater when small PBAT particles were added compared to large ones. PBAT addition at low concentration had no significant effect independent of its size. Overall, the effect of PBAT addition on soil CO2 emissions was larger in sandy loam than in loam. Several bacterial lineages known to degrade polyesters and other biodegradable MPs, such as members of the Caulobacteraceae and Comamonadaceae were found enriched after PBAT amendment, but effects were soil specific. We conclude that direct impacts of plastic on soil properties are not the main reason for increased soil CO2 emissions, but rather relate to the different recalcitrance of polymer types. Soils contaminated with biodegradable plastic may emit larger amounts of CO2, which needs to be considered in predictions of global impacts of plastic pollution and its mitigation.

Effects of biodegradable and non-degradable microplastics on microbial availability and degradation of phenanthrene in soil

Biodegradable plastics have been increasingly used, however, may decompose into microplastics (MPs) more quickly than traditional plastics. In this study, biodegradable polybutylene adipate-co-terephthalate (PBAT) MPs were selected, and non-degradable polyethylene (PE) was used as the reference MPs. The impact of PBAT and PE MPs on microbial availability and degradation of phenanthrene in soil was investigated. The results showed that both the type and addition amount (0.2 % and 2 %, w/w) of MPs significantly affected phenanthrene degradation. Degradation ratio was reduced by the addition of MPs (by 10.6–80.2 %), which was in the order of soil with PBAT > soil with aged PE > soil with PE no matter whether earthworms were present or not. Moreover, compared to PE, addition of PBAT more significantly decreased the concentration of phenanthrene in porewater and the polycyclic aromatic hydrocarbon (PAH)-degrader abundance, which is due to higher sorption affinity of phenanthrene to PBAT and more significant increase in the content of dissolved organic carbon in soil with PBAT, respectively. Additionally, compared to soil without MPs, phenanthrene degradation in soil with MPs was more significantly raised by the presence of earthworms, which is due to a more significant increase in the PAH-degrader abundance.

Determination of Residual Diisocyanates and Related Diamines in Biodegradable Mulch Films Using N-Ethoxycarbonylation Derivatization and GC-MS.

Diisocyanates are highly reactive compounds with two functional isocyanate groups. The exposure of diisocyanates is associated with severely adverse health effects, such as asthma, inflammation in the respiratory tract, and cancer. The hydrolysis product from diisocyanates to related diamines is also a potential carcinogen. Here, we developed an effective, accurate, and precise method for simultaneous determination of residual diisocyanates and related diamines in biodegradable mulch films, based on N-ethoxycarbonylation derivatization and gas chromatography-mass spectrometry. The method development included the optimization of ultrasonic hydrolysis and extraction, screening of N-ethoxycarbonylation conditions with ethyl chloroformate, evaluation of the diamines degradation, and analysis of the fragmentation mechanisms. Under the optimum experimental conditions, good linearity was observed with R2 > 0.999. The extraction recoveries were found in the range of 93.9–101.2% with repeatabilities and reproducibilities in 0.89–8.12% and 2.12–10.56%, respectively. The limits of detection ranged from 0.0025 to 0.057 µg/mL. The developed method was applied to commercial polybutylene adipate co-terephthalate (PBAT) biodegradable mulch film samples for analysis of the diverse residual diisocyanates and related diamine additives. The components varied greatly among the sample from different origin. Overall, this study provides a reliable method for assessing safety in biodegradable mulch films.

Effects of polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) biodegradable microplastics on the abundance and diversity of denitrifying and anammox bacteria in freshwater sediment

Microplastics (MPs) have been widely distributed on Earth and have drawn global concern for freshwater and marine ecosystems. Biodegradable plastics have risen in popularity to replace nonbiodegradable plastics all over the world. The effects of biodegradable plastics on denitrifying and anammox bacteria in freshwater sediment remain largely unknown. In this study, water column reactors containing polylactic acid (PLA) or polybutylene adipate-co-terephthalate (PBAT) MPs in sediment were established to simulate lake ecosystems and analyze the effects of biodegradable MPs on sedimentary nitrogen transformation microorganisms. The total organic carbon (TOC) concentrations in the PLA and PBAT groups were slightly higher than those in the control group, which might be related to the slow degradation of these two plastics. Denitrifying and anammox bacterial diversities decreased after adding MPs to sediments for 30 days, and the dominant OTUs of these two bacteria were differentiated from the control. The abundance levels of nirS denitrifying and anammox bacteria on the PLA MP surface were significantly higher than those in the other groups (P < 0.05), but they were lower in the PBAT groups than in the other groups. As an excellent electron donor for the denitrification process, lactic acid release from PLA degradation resulted in the enrichment of denitrifying and anammox bacteria on the MP surfaces. However, PBAT led to various responses of bacteria in an anaerobic environment. In addition, the redundancy analysis results indicated that total phosphorus, TOC and nitrate were strongly negatively correlated with the abundance levels of denitrifying and anammox bacteria. Our findings provided insight into the effects of MPs, especially the biodegradable ones, on sedimentary nitrogen-transformation bacteria.

Facile production of binary polymer/carbonic nanofiller‐based biodegradable electromagnetic interference shield films with low electrical percolation threshold

AbstractInterference of electromagnetic (EM) radiation generated from different electronic gadgets produces noises diminishing their performance. So, shielding of EM interferences (EMI) is necessary to achieve noise‐free performance from electronic gadgets. In the present work, we have produced thermoplastic polyurethane (TPU)/polybutylene adipate‐co‐terephthalate (PBAT) based biodegradable binary polymeric blend and incorporated different carbonic nanofillers such as Vulcan XC‐72 conductive carbon black (VCB) and multiwalled carbon nanotube (MWCNT) into it employing solvent mixing and casting technique and studied the morphology of polymer blends, EMI shielding effectiveness in X‐band of the EM spectrum as well as mechanical performance, electrical performance, and biodegradability of polymer nanocomposites. The selective nanofiller distribution in the low viscous PBAT phase of the “co‐continuous” binary blend is found to achieve a “lower electrical percolation threshold” compared to neat polymer nanocomposites. For each of the TPU/PBAT/VCB and TPU/PBAT/MWCNT nanocomposites, electrical percolation threshold of around 12.5 and 5 wt% respectively has been achieved successfully. Nanocomposite sheets with a thickness of 1.0 mm and loading of 30 wt% of VCB and 15 wt% of MWCNT gave EMI shielding values of −25 dB and −28 dB respectively at a frequency of 8.4 GHz.

Preparation of functional degradable antibacterial film and application in fresh-keeping of grass carp

To explore new, green and effective low-temperature preservation technology, β -cyclodextrin ( β -CD) embedded Elsholtzia essential oil (EEO) was used as an antibacterial agent, and polybutylene adipate- co -terephthalate (PBAT) and polylactic acid (PLA) were used as the base material to extend grass carp fillets shelf life. Active antibacterial PBAT/PLA, PBAT/PLA-EEO, and PBAT/PLA- β -CD els films were prepared using a casting film-forming process. The changes in total viable count (TVC), pH, total volatile basic nitrogen (TVB-N), and thiobarbituric acid-reactive substances values of grass carp fillets during storage at 4 °C were studied. The results showed that, compared with the PBAT/PLA film, the oxygen transmission rate of PBAT/PLA- β -CD els decreased from 868.02 to 566.80 cm 3 m 2 •24 h•0.1 MPa −1 . During preservation, compared with the PBAT/PLA film, the PBAT/PLA- β -CD els film effectively lowered TVC and delayed TVB-N production. The results revealed that PBAT/PLA- β -CD els film with β -CD-embedded EEO positively affected grass carp quality maintenance and extended its shelf life. Overview of the experiments. PLA pellets and PBAT pellets were blended with β -CD els . After the modified resins were prepared using a single-screw plastic extrusion device to obtain active films. Then apply it to the preservation of grass carp. • We explored a new, green, and effective low-temperature preservation technology. • β -cyclodextrin-embedded Elsholtzia essential oil was used as an antibacterial agent. • Polybutylene adipate- co -terephthalate and polylactic acid were used as a base. • Fresh-keeping was assessed in grass carp fillets preserved in β -CD-embedded EEO. • The film with positively affected grass carp quality and extended its shelf life.

Effects of microplastics on common bean rhizosphere bacterial communities

Microplastic pollution in terrestrial ecosystems is a growing concern due to its potential influences on soil properties and crop growth. Little is known about the effects of microplastics on the microbiome in the rhizosphere. Here, we studied the effects of two types of microplastics (MPs), low density polyethylene (LDPE-MPs) and biodegradable microplastic (Bio-MPs) of poly-butylene-adipate-co-terephthalate (PBAT) mixed with polylactic acid (PLA), on rhizosphere bacterial communities of Phaseolus vulgaris at doses of 0.5 %, 1.0 % and 2.5 % (w/w, dry weight ratio between MPs and soil). Bio-MPs and LDPE-MPs showed significant higher α-diversity (Chao 1, ACE, Shannon and Simpson) than control. For each type of microplastic material, 2.5 % of LDPE-MPs and Bio-MPs showed lowest α-diversity as compared to doses of 0.5 % and 1.0 %, indicating 2.5 % dose of MPs might pose selective effect on rhizosphere bacterial communities. β-Diversity of 1.0 % and 2.5 % Bio-MPs were distinctive from the control and other treatments. Microplastics also affected the relative abundance at family level, i.e. as compared to control, Comamonadaceae was higher in all the MPs treatments, Rhizobiaceae was highest in 2.5 % LDPE-MPs and lowest in 2.5 % Bio-MPs. LefSe results showed, as compared to control, Bio-MPs induced more indictive taxa than LDPE-MPs. Our findings evidenced that LDPE-MPs and Bio-MPs exerted profound effects on rhizosphere bacterial communities, and these effects might have far-reaching effects on soil nutrient cycling and plant health in agroecosystems.

Novel silver-modified carboxymethyl chitosan antibacterial membranes using environment-friendly polymers

The rapid reproduction of foodborne bacteria in food packaging threatens the health of consumers, the massive use and waste of packaging also causes serious environmental pollution. In this study, novel biodegradable antibacterial membranes based on silver-modified carboxymethyl chitosan (Ag-CMCS) were prepared. Polylactic acid (PLA) and polybutylene adipate-co-terephthalate (PBAT) were used as the base membrane materials. Characterization of the prepared membranes was performed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS), water contact angle, and so on. Especially, the silver on the surface of Ag-CMCS was proved to be metallic silver. For the first cycle of zone of inhibition test, the diameter of inhibition zone could reach up to 17 mm while the mass of silver released was negligible. The prepared antibacterial membranes could kill almost 100% of bacteria under certain conditions and inhibition zone still existed after more than 7 cycles of tests, indicating the prepared antibacterial membranes were effective. This study could provide new ideas for preparing efficient and environment-friendly antibacterial food packaging membranes.

Biodegradable polymers based on natural carotenoids

Carotenoids such as curcumin and bixin are polyisoprenoids, and are responsible for red, orange or yellow colors. Curcumin is a yellow hydrophobic polyphenol that presents a low molecular weight. Bixin is a natural color extracted from the Annato tree and its color varies from yellow to red due to the presence of the isomer carotenoid trans-bixin. Food and cosmetic industries use them due to their antioxidant properties. The biodegrading properties of polymer blends can be improved by the addition of vegetable oil, organic and inorganic additives or by mixing them with a biodegradable polymer. According to previous studies, polymers produced by a mixture of Moringa polymer (PMO), polyethylene (PE) and commercial biodegradable polymers (PB), composed of PBAT (poly(butylene adipate-co-terephthalate)/PLA (polylactic acid), presented mechanical properties similar to those of PE, except for a higher biodegradation capacity. Vegetable oils can be used as plasticizers for polymer blends and Moringa oil and improved the biodegradation properties in other studies.

Biodegradation of polybutylene adipate-co-terephthalate by Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes following incubation in the soil

Soil that contained polybutylene adipate-co-terephthalate (PBAT) was incubated with Priestia megaterium, Pseudomonas mendocina, and Pseudomonas pseudoalcaligenes to improve the biodegradative process of this polymer. The mixture of Pr. megaterium and Ps. mendocina was highly effective at biodegrading the PBAT, and after eight weeks of soil incubation, approximately 84% of the PBAT film weight was lost. Mixtures of the other two species also positively affected the synergistic degradation of PBAT film in the soil, but the mixture of three species had a negative effect. The residual PBAT film microstructure clearly demonstrated the degradation of PBAT, and the degree of degradation was related to the different species. Cleavage of the PBAT film ester bond after soil microbial action affected its properties. The incubation of PBAT in soil that contained these species affected soil dehydrogenase and soil lipase in particular. The secretion of lipase by these species could play an important role in the degradation of PBAT in the soil.

Migration, aggregations and thermal degradation behaviors of TiO2 and ZnO incorporated PBAT/TPS nanocomposite blown films

Metal oxides including titanium dioxide (TiO2) and zinc oxide (ZnO) enhanced the properties and functional performance of biodegradable plastic food packaging. Effects of TiO2 and ZnO nanofillers (1-5%) on bioplastic packaging microstructural changes were investigated for infrared absorption, thermal stability and migration behavior in distilled water, 10% ethanol and 3% acetic acid. Nanoparticles were compounded with thermoplastic starch (TPS) before blending with polybutylene adipate-co-terephthalate (PBAT), and converted into nanocomposite films via blown-film extrusion. Microstructural analysis indicated that addition of TiO2 and ZnO enhanced disruption of starch granules, increasing the amorphous starch portion. Energy dispersive X-ray analysis (EDX) exhibited higher aggregations of TiO2 particles than ZnO, coincident with higher degree of hydrogen bonding between ZnO and TPS phase. Strong interaction between ZnO and polymers also modified degradation temperatures (Td) of both PBAT and TPS phase in PBAT/TPS blend films. TiO2 gave identical Td but higher residual mass depending on nanocomposite amounts that modified the amorphous-crystalline fraction. Films with ZnO had higher migration levels, particularly in acid simulant due to high dissolution of ZnO particles, analyzed by inductively coupled plasma mass spectrometry. Release of titanium was strongly dependent on simulant types, showing maximum at 3-4% TiO2 followed by a sharp drop at higher TiO2 levels. Films containing ZnO showed higher migration levels, indicating that films containing TiO2 were more inert. Migration levels of titanium and zinc metals from TiO2 and ZnO incorporated PBAT/TPS blown films were influenced by alteration of the matrix structure due to simulant penetrations, interaction and adhesion forces between metals and polymers and favorable dissolution of the metal into simulants. Interaction between simulant-polymer and simulant-metal oxide particles further modified film matrices and enhanced release. The films showed promise for use in aqueous surroundings for food applications.

Stretchability and Deformation Behavior of Polybutylene Adipate-co-terephthalate Blend Films

The single use packaging is widely used in various products; ranging from food to non-food contact, from commodity to specialty purposes. Most of these materials are derived from non-renewable fossil resources. In a sustainable manner, it needs to be recyclable or compostable. Good mechanical properties together with biodegradability can make the product more recyclable. In this study, the elasticity for films consisting of polybutylene adipate-co-terephthalate (PBAT) blended with polylactic acid (PLA) (10, and 20 %wt), additive and reactive agents were evaluated. The blends were prepared via a twin-screw extruder. The film specimens were prepared by cast film extrusion. The films were then stretched with different ratios (1.5, 2 and 2.5 times) by the uniaxial machine. The mechanical properties, elasticities and surface morphology of uniaxially stretched PBAT and PBAT blend films were characterized by tensile testing and scanning electron microscope (SEM), respectively. The tensile strength of stretched films tended to improve while the elongation at break reduced at higher stretching ratios. The surface morphology of stretched films revealed that the degree of orientation was increased after higher stretching ratios. The ability to recover in the plastic deformation region of stretched films was increased at the higher stretching ratios.

Structure and Properties of PBS/PBAT blends and nanocomposites

The use of bio-compostable polymers such as Polybutylene Succinate (PBS), Polybutylene Adipate Co-Terephthalate (PBAT) or Polylactic acid is restricted due to the barrier properties especially the water vapor transmission rate (WVTR) which is high in these commercially available polymers. The WVTR plays an important role in preserving the freshness of fruits and vegetables and it has to be optimum. Polymer blending and incorporation of nano fillers are facile routes to formation of internal structure and morphology which gives good control of barrier properties of films. Hence, crystalline structure and morphology of PBS-PBAT blends were studied in detail with respect to composition of the blend. The effect of nanofillers (Halloysite nanotubes/HNT) incorporation as well as addition of polyethylene glycol (PEG) as plasticizer on crystallization process was also investigated. The samples were cast on a glass plate substrate from solution using membrane caster at constant speed and thickness in the range of 100 microns. The composition was varied from 0 to 40 % of PBS in PBAT matrix while addition of HNT was varied from 1 to 5%. Films were air dried in an oven at 50-55 °C for 6 hr. The crystal structure development was studied using wide angle X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC) and the molecular interaction examined using FTIR. XRD data indicated that PBS crystals were in monoclinic α phase but the relative intensities of the 011 and 020 reflections changed drastically in the blends. The DSC analysis revealed that there was preferential growth of PBS α phase crystals with sharp melting at 110 °C. The HNT gave distinct nucleation effect with a shift in the Tc peak as well as increase of ΔHc value. The preferential nucleation by HNT could be associated with the close lattice match for the HNT and the monoclinic phase of PBS. FTIR studies indicate that the all the contents were dispersed well and show hydrogen bonding interaction at the –OH and –COOH groups. These changes in the crystallinity and crystal phase improved the barrier properties leading to the decrease in (WVTR) with the addition of PBS to PBAT as well as incorporation of HNT in the blend. WVTR decreased from 120 g/m2/day to 55 g/m2/day which is excellent for packaging of green agriculture produce.

Toughening polylactic acid by melt blending with polybutylene adipate‐co‐terephthalate and natural rubber, and the performance of the resulting ternary blends

AbstractPolylactic acid (PLA) is one of the most commercially potential bio‐based and biodegradable materials recently used to partially replace non‐biodegradable petroleum‐based plastics; however, PLA's innate brittleness limits its practical applications. The present work aims to reduce the brittleness and improve the toughness of PLA by blending it with polybutylene adipate‐co‐terephthalate (PBAT) and natural rubber (NR). PLA/PBAT/NR ternary blends were prepared by a melt blending process, using both an internal mixer and a twin‐screw extruder, and were converted into test specimens using an injection molding machine. The weight ratio of PBAT:NR was kept constant at 1:1, while the amounts of PBAT/NR blend were varied at 14, 26, and 38 wt%. SEM confirmed the incompatibility among PLA, PBAT, and NR, as island‐like NR phases and oval PBAT phases were dispersed in the PLA matrix. Compared with neat PLA, the PLA/PBAT/NR ternary blends exhibited increased elongation at break from 6.2% to 21.0% (up to 240%), improved impact strength from 36.6 to 85.0 J/m (up to 130%), decreased density from 1.254 to 1.159 g/cm3 (approximately 7.6%), enhanced thermal stability and water resistance, and reduced shear‐dependent behavior. The obtained PLA/PBAT/NR blends have potential for the production of injection‐molded articles such as biomedical devices, toys, agricultural supplies, office supplies.