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1.
Small ; 20(3): e2305181, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37699749

RESUMO

As a steady stream of electronic devices being discarded, a vast amount of electronic substrate waste of petroleum-based nondegradable polymers is generated, raising endless concerns about resource depletion and environmental pollution. With coupled reagent (CR)-grafted artificial marble waste (AMW@CR) as functional fillers, polylactic acid (PLA)-based highly stretchable biodegradable green composite (AMW@CR-SBGC) is prepared, with elongation at break up to more than 250%. The degradation mechanism of AMW@CR-SBGC is deeply revealed. AMW@CR not only contributed to the photodegradation of AMW@CR-SBGC but also significantly promoted the water degradation of AMW@CR-SBGC. More importantly, AMW@CR-SBGC showed great potential as sustainable green electronic substrates and AMW@CR-SBGC-based electronic skin can simulate the perception of human skin to strain signals. The outstanding programmable degradability, recyclability, and reusability of AMW@CR-SBGC enabled its application in transient electronics. As the first demonstration of artificial marble waste in electronic substrates, AMW@CR-SBGC killed three birds with one stone in terms of waste resourcing, e-waste reduction, and saving nonrenewable petroleum resources, opening up vast new opportunities for green electronics applications in areas such as health monitoring, artificial intelligence, and security.

2.
Molecules ; 29(1)2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-38202809

RESUMO

The development of fully renewable and biodegradable composites for short-term applications was pursued by combining a compatibilized poly(lactic acid) (PLA)/poly(butylene succinate-co-adipate) (PBSA) (60:40 wt:wt) blend with coffee silver skin (CSS), an industrial byproduct from coffee processing. An epoxy-based reactive agent (Joncryl ADR-4468) was added as a compatibilizer. CSS was incorporated at 5, 10, and 20 wt% in the blend both in the as-received state and after a simple thermal treatment in boiling water, which was performed to mitigate the negative impact of this filler on the rheological and mechanical properties of the blend. The CSS treatment effectively increased the filler degradation temperature of 30-40 °C, enabling stable melt processing of the composites. It also improved filler-matrix adhesion, resulting in enhanced impact properties (up to +172% increase in impact energy compared to the untreated filler). Therefore, treated CSS demonstrated potential as an effective green reinforcement for PLA/PBSA blends for rigid packaging applications. Future works will focus on studying suitable surface modification of CSS to further increase the interfacial interaction and the tensile quasi-static properties, to fully exploit the capabilities of this renewable material toward the development of eco-friendly composites.

3.
Int J Mol Sci ; 21(24)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33353232

RESUMO

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.


Assuntos
Hidroxibutiratos/química , Queratinas/química , Plastificantes/química , Poliésteres/química , Polímeros/química , Reologia , Temperatura
4.
Int J Biol Macromol ; 266(Pt 1): 130869, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38493822

RESUMO

In this study, starch-based biodegradable composites (SDC) were prepared by extruding using thermoplastic starch (TPS, 65%wt), polylactic acid (PLA, 30%wt) and poly (butylene adipate co-terephthalate) (PBAT, 5%wt). Structure and properties of the SDC were compared by performing 1-, 2-, 3-times extrusion. The results show that in-situ re-extrusion refines the TPS in composites and reduces the size of the phase. As the number of extrusions increases, the ester bond of composites at 868 cm-1 disappears, the crystallinity increases, and the thermal stability decreases. Among the three types of composites, the mechanical properties and hydrophobic properties of the material obtained by the 2-times are the most outstanding. Compared with SDC, the elongation at break and Young's modulus of SDC-2 are significantly increased, with an increase of 8.01 % and 1.28 % in the machine direction and an increase of 11.02 % and 1.79 % in the transverse direction respectively. Additionally, water contact angle range of SDC-2 from 98.7° to 101.7°. Therefore, SDC prepared by 2-times in-situ re-extrusion has the best film properties and is an ideal packaging material. This study presents a novel method for fabricating starch-degradable composite films by in-situ re-extrusion, providing new insights into the development of starch packaging materials.


Assuntos
Poliésteres , Amido , Amido/química , Poliésteres/química , Interações Hidrofóbicas e Hidrofílicas , Módulo de Elasticidade , Água/química , Temperatura
5.
Int J Biol Macromol ; 270(Pt 1): 132070, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38705313

RESUMO

Plastic pots used in horticultural nurseries generate substantial waste, causing environmental pollution. This study aimed to develop biodegradable composites from banana pseudo-stem reinforced with agricultural residues like pineapple leaves, taro and water hyacinth as eco-friendly substitutes. The aim of this study is to develop optimised banana biocomposite formulations with suitable reinforcements that balance mechanical durability, biodegradation, and seedling growth promotion properties to serve as viable eco-friendly alternatives to plastic seedling pots. This study was carried out by fabricating banana fibre mats through pulping, drying and hot pressing. Composite sheets were reinforced with 50 % pineapple, taro or water hyacinth fibres. The mechanical properties (tensile, yield strength, elongation, bursting strength), hydrophilicity (contact angle, water absorption), biodegradability (soil burial test), and seedling growth promotion were evaluated through appropriate testing methods. The results show that banana-taro composites exhibited suitable tensile strength (25 MPa), elongation (27 %), water uptake (41 %) and 82 % biodegradation in 60 days. It was observed that biodegradable seedling trays fabricated from banana-taro composite showed 95 % tomato seed germination and a 125 cm plant height increase in 30 days, superior to plastic trays. The finding shows that the study demonstrates the potential of banana-taro biocomposites as alternatives to plastic nursery pots, enabling healthy seedling growth while eliminating plastic waste pollution through biodegradation.


Assuntos
Musa , Plântula , Musa/crescimento & desenvolvimento , Musa/química , Plântula/crescimento & desenvolvimento , Resistência à Tração , Biodegradação Ambiental , Germinação , Água/química
6.
Polymers (Basel) ; 16(16)2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39204551

RESUMO

Interesting alternatives to expensive biodegradable polymers are their composites with natural fillers. The addition of biochar to a blend of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) was studied, and the resulting materials were evaluated for their properties and changes during degradation. Introducing biochar as a filler brought a noticeable improvement in electrostatic properties. Surface resistivity decreased from 3.80 × 1012 for the sample without biochar to 1.32 × 1012 for the sample with 30% filler content. Degradation tests revealed distinct differences in the degradation profile for composites due to the presence of filler. Composites with a lower biochar content displayed curling crack edges during hydrolytic degradation, and when the filler content reached 20 wt%, PLA loss accelerated. This study suggests that biochar-based composites have potential to be used as sustainable materials with improved properties.

7.
Polymers (Basel) ; 15(19)2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37836043

RESUMO

The development of innovative biomaterials with improved integration with bone tissue and stimulating regeneration processes is necessary. Here, we evaluate the usefulness of bioactive glasses from the SiO2-P2O5-CaO system enriched with 2 wt.% SrO or ZnO in the manufacturing of chitosan-based scaffolds. Bioglasses produced using the sol-gel method were subjected to thermal treatment in different regimes. Chitosan/bioglass composites were produced with a weight ratio. Bioglasses were evaluated via TG-DTA, FTIR, and SEM-EDS before and after incubation in simulated body fluid (SBF). The release of ions was tested. The cytocompatibility of the composites in contact with MG63 osteoblast-like cells was evaluated. The results showed that the presence of the crystalline phase decreased from 41.2-44.8% for nonmodified bioglasses to 24.2-24.3% for those modified with ZnO and 22.0-24.2% for those modified with SrO. The samples released Ca2+, Zn2+, and/or Sr2+ ions and were bioactive according to the SBF test. The highest cytocompatibility was observed for the composites containing nonmodified bioglasses, followed by those enriched with SrO bioglasses. The least cytocompatible were the composites containing ZnO bioglasses that released the highest amount of Zn2+ ions (0.58 ± 0.07 mL/g); however, those that released 0.38 ± 0.04 mL/g were characterised by acceptable cytocompatibility. The study confirmed that it is feasible to control the biological performance of chitosan/bioglass composites by adjusting the composition and heat treatment parameters of bioglasses.

8.
Carbohydr Polym ; 305: 120535, 2023 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-36737188

RESUMO

In this paper, we proposed a novel and green strategy based on water evaporation induced in-situ interfacial compatibilization (WEIC) mechanism for fabricating high-strength and all-natural lignocellulose/starch composites. This mechanism exploits the natural compatibility of the lignocellulose and starch and was tested through an internal mixing process with regulated water evaporation. Specifically, we revealed that a restrained layer was in-situ formed at the interface of the lignocellulose and starch during the internal mixing process; a faster water evaporation rate thickens this restrained layer, restricts the starch's molecular movement and significantly increases the composite's mechanical properties. The highest tensile strength and Young's modulus of the composites achieved are 21.7 ± 0.8 MPa and 2.2 ± 0.1 GPa, respectively, superior to many existing starch/lignocellulose composites. Thus, this work provides new insight into the compatibilization of various hydrophilic polysaccharides and paves new avenues for developing greener and more facile methods to fabricate all-polysaccharide composites.

9.
Materials (Basel) ; 16(5)2023 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-36903020

RESUMO

This study reports the development of magnesium alloy/hydroxyapatite-based biodegradable metal matrix composites (BMMCs) through rapid microwave sintering. Magnesium alloy (AZ31) and hydroxyapatite powder were used in four compositions 0, 10, 15 and 20% by weight. Developed BMMCs were characterized to evaluate physical, microstructural, mechanical and biodegradation characteristics. XRD results show Mg and HA as major phases and MgO as a minor phase. SEM results correlate with the XRD findings by identifying the presence of Mg, HA and MgO. The addition of HA powder particles reduced density and increased the microhardness of BMMCs. The compressive strength and Young's modulus increased with increasing HA up to 15 wt.%. AZ31-15HA exhibited the highest corrosion resistance and lowest relative weight loss in the immersion test for 24 h and weight gain after 72 and 168 h due to the deposition of Mg(OH)2 and Ca(OH)2 layers at the sample surface. XRD analysis of the AZ31-15HA sintered sample after an immersion test was carried out and these results revealed the presence of new phases Mg(OH)2 and Ca(OH)2 that could be the reason for enhancing the corrosion resistance. SEM elemental mapping result also confirmed the formation of Mg(OH)2 and Ca(OH)2 at the sample surface, which acted as protective layers and prevented the sample from further corrosion. It showed that the elements were uniformly distributed over the sample surface. In addition, these microwave-sintered BMMCs showed similar properties to the human cortical bone and help bone growth by depositing apatite layers at the surface of the sample. Furthermore, this apatite layer can enhance osteoblast formation due to the porous structure type, which was observed in the BMMCs. Therefore, it is indicative that developed BMMCs can be an artificial biodegradable composite for orthopedic applications.

10.
Polymers (Basel) ; 15(3)2023 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-36771880

RESUMO

Nowadays, the search for new materials with a sustainable character to reduce the production of residues is under continuous research. In this sense, fully biodegradable composites based on polyhydroxybutyrate and different pretreated fibres coming from barley straw have been fabricated, and their resistance to environmental controlled conditions have been characterized. The materials were already compounded in a kinetic mixer and injection-moulded as specimens for tensile assay to be aged in a Xenotest chamber so as to simulate environmental conditioning. The samples, after accelerated aging, were characterized thus: mechanical characterization (tensile assay), water uptake (immersion and contact angle), and surface observation (optical and SEM microscopy). The incorporation of the fibres helps the composite to keep its structure for a longer time. On the other hand, the presence of the fibres increases the water uptake capacity to allow water permeation in the composite, which allows final degradation, characterised by a significant drop in properties after one month of exposure to simulated environmental conditions.

11.
Materials (Basel) ; 15(18)2022 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-36143522

RESUMO

The poly(lactic acid) (PLA) biodegradable polymer, as well as natural, siliceous reinforcement in the form of diatomaceous earth, fit perfectly into the circular economy trend. In this study, various kinds of commercial PLA have been reinforced with diatomaceous earth (DE) to prepare biodegradable composites via the extrusion process. The structure of the manufactured composites as well as adhesion between the matrix and the filler were investigated using scanning electron microscopy (SEM). Differential scanning calorimetry (DSC) analyses were carried out to determine crystallinity of PLA matrix as function of DE additions. Additionally, the effect of the ceramic-based reinforcement on the mechanical properties (Young's modulus, elongation to failure, ultimate tensile strength) of PLA has been investigated. The results are discussed in terms of possible applications of PLA + DE composites.

12.
Front Chem ; 10: 1119978, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36712983

RESUMO

Modifying biodegradable poly (butylene adipate-co-terephthalate) (PBAT) plastic with inorganic fillers is critical for improving its overall performance, lowering the costs, and expanding its application scope. The chemical modification method for the inorganic filler determines the application performance of PBAT composites. In this work, gas-solid fluidization method was developed as a simple, efficient, and scalable strategy for chemically modifying CaCO3 filler. The modified CaCO3 filler was mixed with PBAT and melt extruded to prepare biodegradable PBAT/CaCO3 composites. The characterization results show that gas-solid fluidization method combines the traditional wet modification method's excellent modification effect with the scalability of the traditional dry modification method. The effects of modification methods and amount of CaCO3 filling on the crystallinity, mechanical, and rheological properties of PBAT/CaCO3 composites were compared. The results demonstrated that PBAT/CaCO3 composites containing 30% gas-solid fluidization modified CaCO3 could still maintain excellent overall performance. As a result, this work provides a simple, efficient, and scalable method for chemically modifying inorganic fillers and preparing biodegradable composites.

13.
Artigo em Inglês | MEDLINE | ID: mdl-35830227

RESUMO

Biodegradable conductive composites are key materials or components for printable transient electronics that can be fabricated in a low-cost and high-efficiency manner, thereby boosting their wide applications in biomedical engineering, hardware security, and environmental-friendly electronics. Continuous efforts in this area still lie in the development of strategies for highly conductive, safe, and reliable biodegradable conductive composite materials and devices. This paper introduces molybdenum/wax composites for multimodally printable transient electronics in which multiple transience modes including dissolution-induced degradation and thermally triggered degradation are available. Systematic experiments demonstrate several advantages and unique properties of this material system, including solvent-free fabrication, self-sintering behavior, and long-term and high conductivity via accelerable self-sintering treatment and rehealing capabilities. Notably, the immersion of molybdenum/wax composites in phosphate buffer solution can provide both positive effects (accelerated self-sintering-dominated) and negative effects (degradation-dominated) on their electrical conductivities. Mechanism analyses reveal the basis for balancing the degradation and accelerated self-sintering processes. The presented demonstrations foreshadow opportunities of the developed molybdenum/wax composites in rehealable electronics, on-demand smart transient electronics with multiple transience modes, and many other related unusual applications.

14.
Materials (Basel) ; 15(1)2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-35009460

RESUMO

Lactic acid oligomers (OLAs) were in situ synthesized from lactic acid (LAc) and grafted onto chokeberry pomace (CP) particleboards by direct condensation. Biocomposites of poly (lactic acid) (PLA) and modified/unmodified CP particles containing different size fractions were obtained using a mini-extruder. To confirm the results of the grafting process, the FTIR spectra of filler particles were obtained. Performing 1HNMR spectroscopy allowed us to determine the chemical structure of synthesized OLAs. The thermal degradation of modified CP and biocomposites were studied using TGA, and the thermal characteristics of biocomposites were investigated using DSC. In order to analyse the adhesion between filler particles and PLA in biocomposites, SEM images of brittle fracture surfaces were registered. The mechanical properties of biocomposites were studied using a tensile testing machine. FTIR and 1HNMR analysis confirmed the successful grafting process of OLAs. The modified filler particles exhibited a better connection with hydrophobic PLA matrix alongside improved mechanical properties than the biocomposites with unmodified filler particles. Moreover, a DSC analysis of the biocomposites with modified CP showed a reduction in glass temperature on average by 9 °C compared to neat PLA. It confirms the plasticizing effect of grafted and ungrafted OLAs. The results are promising, and can contribute to increasing the use of agri-food lignocellulosic residue in manufacturing biodegradable packaging.

15.
J Biomed Mater Res B Appl Biomater ; 110(11): 2422-2437, 2022 11.
Artigo em Inglês | MEDLINE | ID: mdl-35618683

RESUMO

The manufacturing of modern scaffolds with customized geometry and personalization has become possible due to the three-dimensional (3D) printing technique. A novel type of 3D-printed scaffolds for bone tissue regeneration based on poly(ε-caprolactone) (PCL) filled with nanocrystalline cellulose modified by poly(glutamic acid) (PGlu-NCC) has been proposed in this study. The 3D printing set-ups were optimized in order to obtain homogeneous porous scaffolds. Both polymer composites and manufactured 3D scaffolds have demonstrated mechanical properties suitable for a human trabecular bone. Compression moduli were in the range of 334-396 MPa for non-porous PCL and PCL-based composites, and 101-122 MPa for porous scaffolds made of the same materials. In vitro mineralization study with the use of human mesenchymal stem cells (hMSCs) revealed the larger Ca deposits on the surface of PCL/PGlu-NCC composite scaffolds. Implantation of the developed 3D scaffolds into femur of the rabbits was carried out to observe close and delayed effects. The histological analysis showed the lowest content of immune cells and thin fibrous capsule, revealing low toxicity of the PCL/PGlu-NCC scaffolds seeded with rabbit MSCs (rMSCs) to the surrounding tissues. The most pronounced result on the generation of new bone tissue after implantation of PCL/PGlu-NCC + rMSCs scaffolds was detected by both microcomputed tomography and histological analysis. Around 33% and 55% of bone coverage were detected for composite 3D scaffolds with adhered rMSCs after 1 and 3 months of implantation, respectively. This achievement can be a result of synergistic effect of PGlu, which attracts calcium ions, and stem cells with osteogenic potential.


Assuntos
Nanopartículas , Alicerces Teciduais , Animais , Regeneração Óssea , Osso e Ossos , Cálcio , Caproatos , Celulose/farmacologia , Ácido Glutâmico , Humanos , Lactonas , Poliésteres/química , Poliésteres/farmacologia , Impressão Tridimensional , Coelhos , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Microtomografia por Raio-X
16.
Polymers (Basel) ; 13(16)2021 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-34451232

RESUMO

From environmental aspects, the recovery of keratin waste is one of the important needs and therefore also one of the current topics of many research groups. Here, the keratin hydrolysate after basic hydrolysis was used as a filler in plasticized polylactic acid/poly(3-hydroxybutyrate) blend under loading in the range of 1-20 wt%. The composites were characterized by infrared spectroscopy, and the effect of keratin on changes in molar masses of matrices during processing was investigated using gel permeation chromatography (GPC). Thermal properties of the composites were investigated using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The effect of keratin loading on the mechanical properties of composite was investigated by tensile test and dynamic mechanical thermal analysis. Hydrolytic degradation of matrices and composites was investigated by the determination of extractable product amounts, GPC, DSC and NMR. Finally, microbial growth and degradation were investigated. It was found that incorporation of keratin in plasticized PLA/PHB blend provides material with good thermal and mechanical properties and improved degradation under common environmental conditions, indicating its possible application in agriculture and/or packaging.

17.
J Mech Behav Biomed Mater ; 123: 104781, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34482093

RESUMO

The shear strength and the corrosion resistance of the fiber/matrix interface after immersion in simulated body fluid was studied in poly-lactic acid/Mg fiber composites. The shear strength of the interface was measured by means of push-out tests in thin slices of the composite perpendicular to the fibers. It was found that the interface strength dropped from 15.2 ± 1.4 MPa to 7.8 ± 3.7 MPa after the composite was immersed in simulated body fluid for 148 h. The reduction of the interface strength was associated to the fast corrosion of the fibers as water diffused to the interface through the polymer. The expansion of the fibers due to the formation of corrosion products was enough to promote radial cracks in the polymer matrix which facilitate the ingress of water and the development of corrosion pitting in the fibers. Moreover, cell culture testing on the material showed that early degradation of the Mg fibers affected the proliferation of pre-osteoblasts near the Mg fibers due to the local changes in the environment produced by the fiber corrosion. Thus, surface modification of Mg fibers to delay degradation seems to be a critical point for further development of Mg/PLA composites for biomedical applications.


Assuntos
Implantes Absorvíveis , Poliésteres , Corrosão , Ácido Láctico , Polímeros
18.
Polymers (Basel) ; 13(10)2021 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-34064585

RESUMO

The surface properties of wood fiber (WF) filled polymer composites depend on the filler loading and are closely related to the distribution and orientation in the polymer matrix. In this study, wood fibers (WF) were incorporated into thermoplastic composites based on non-recycled polypropylene (PP) and recycled (R-PP) composites by melt compounding and injection moulding. ATR-FTIR (attenuated total reflection Fourier transform infrared spectroscopy) measurements clearly showed the propagation of WF functional groups at the surface layer of WF-PP/WF-R-PP composites preferentially with WF loading up to 30%. Optical microscopy and nanoindentation method confirmed the alignment of thinner skin layer of WF-PP/WF-R-PP composites with increasing WF addition. The thickness of the skin layer was mainly influenced by the WF loading. The effect of the addition of WF on modulus and hardness, at least at 30 and 40 wt.%, varies for PP and R-PP matrix. On the other hand, surface zeta potential measurements show increased hydrophilicity with increasing amounts of WF. Moreover, WF in PP/R-PP matrix is also responsible for the antioxidant properties of these composites as measured by DPPH (2,2'-diphenyl-1-picrylhydrazyl) assay.

19.
Materials (Basel) ; 13(3)2020 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-32050633

RESUMO

Due to the hydrophobic nature of poly (butylene terephthalate) (PBAT), and the hydrophilic nature of bamboo flour (BF), a BF/PBAT (50/50) blend shows low mechanical properties, and especially shows poor impact strength. In order to increase the interfacial adhesion between BF and PBAT, diisocyanate was used as a reactive compatibilizer to modify bamboo powder. A series of BF/PBAT composites were prepared by the method of mixing and melting in an internal mixer. After adding reactive compatibilizer 4,4'-methylenebis(phenyl isocyanate) (MDI), BF/PBAT (50/50) composites with high mechanical properties were successfully prepared. The tensile strength, elongation at break, and impact strength of the BF/MDI-2/PBAT composite with 2 wt % MDI content were increased by 1.9, 6.8, and 4.3 times respectively over the BF/PBAT blend without the added MDI. The higher toughening effect of MDI in BF/PBAT composites can be mainly ascribed to the improved interface bonding between BF and PBAT. The isocyanate group of MDI can react with the hydroxyl group on the BF surface and in situ formation of the carbamate group on the BF surface. The residual isocyanate can then react with the hydroxyl group of PBAT and form carbamate groups. The rheological behaviors demonstrate that addition of appropriate amounts of MDI, 1 wt % and 2 wt %, can promote the flowability of the molten BF/PBAT composites due to the decrease in interparticle interaction between bamboo powder and the increase in the thermal motion of the molecules.

20.
Materials (Basel) ; 13(9)2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403315

RESUMO

The need for a cost reduction of the materials derived from (bio)degradable polymers forces research development into the formation of biocomposites with cheaper fillers. As additives can be made using the post-consumer wood, generated during wood products processing, re-use of recycled waste materials in the production of biocomposites can be an environmentally friendly way to minimalize and/or utilize the amount of the solid waste. Also, bioactive materials, which possess small amounts of antimicrobial additives belong to a very attractive packaging industry solution. This paper presents a study into the biodegradation, under laboratory composting conditions, of the composites that consist of poly[(R)-3-hydroxybutyrate-co-4-hydroxybutyrate)] and wood flour as a polymer matrix and natural filler, respectively. Thermogravimetric analysis, differential scanning calorimetry and scanning electron microscopy were used to evaluate the degradation progress of the obtained composites with different amounts of wood flour. The degradation products were characterized by multistage electrospray ionization mass spectrometry. Also, preliminary tests of the antimicrobial activity of selected materials with the addition of nisin were performed. The obtained results suggest that the different amount of filler has a significant influence on the degradation profile.

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