Green Filler Research Articles

Improved physical properties and in vitro biocompatibility of chitosan composite scaffolds incorporated with a green filler on bone cells

Scaffolds to facilitate three-dimensional bone ingrowth have been widely researched for bone regeneration. Fish scale can serve as a green filler for the reinforcement of chitosan scaffolds as it contains type I collagen and hydroxyapatite (HAp) which will promote osteoblastic functions. In the current study, chitosan scaffolds were incorporated with fish scale at a weight percent (wt%) range of 12–20. The composite scaffolds with interconnected pore and porosity of 26–142 μm and 58.2–76.1%, respectively, exhibited an improved compressive modulus ranging from 0.905 to 1.1 MPa. The improved mechanical property of chitosan–fish scale (C–FS) scaffolds was also coupled with reduced degradation rates of 9.3–14.3%. Fluorescence microscopic observation showed that the cell adhesion was peaked on the C–FS scaffold with 18 wt% of fish scale at the density of 1.05 ± 0.39 cells/mm2. Subsequently, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay showed that the cell proliferation on C–FS scaffolds was significantly higher (p < 0.05) than that of control cells. Furthermore, the early differentiation of MG63 measured using alkaline phosphatase assay revealed the highest peak at 14-day culture on the scaffolds. These findings clearly signified the potential incorporation of fish scale at 18 wt% into chitosan scaffolds for reinforcement purpose by promoting the highest osteoblastic adhesion, proliferation and early differentiation.

Toughening Effect of Rodlike Cellulose Nanocrystals in Epoxy Adhesive

Epoxy structural adhesives have been used extensively in the automotive and aerospace industries to bond assembly parts. Much effort has been devoted to enhancing the mechanical properties of epoxy resin by incorporating fillers. Among a variety of fillers investigated for this purpose, nanocelluloses are regarded as a promising type of emerging green filler material because of their excellent mechanical and physicochemical properties. Indeed, nanocelluloses have been used as a filler for polymer nanocomposites. However, the toughening and reinforcing effects of nanocelluloses on rigid epoxy adhesives have not yet been fully revealed, particularly from the perspective of adhesive bonded joints. Here we report that epoxy adhesive containing cellulose nanocrystal (CNC) aggregates produced using a solvent-free ball milling method achieves drastically improved adhesive strength and fracture toughness compared with that of the reference adhesive without CNCs. The epoxy adhesive containing CNC aggregates exhibi...

The use of Biochar to reduce the carbon footprint of cement-based materials

The organic waste management is a most current topic, because its processing and degradation it is responsible for emissions of methane and other greenhouse gases, leading to serious environmental problems. Limited oxygen thermochemical processes, such as pyrolysis or gasification, have demonstrated the energy recovery potential of the treated biomass and its environmental benefits. However, the solid part of the process -Biochar- it is considered as a waste, as only its coarse ash can be used as soil improvers. Nevertheless, several researchers have explored its potential application as green filler in order to reduce the carbon footprint both of cement production and cement-based construction materials. In this work, Biochar microparticles were used both as a filler inside the cement paste and mortar composites and as a substitute for the cement powder inside the mixes. Based on previous work, this investigation has a twofold objective: to understand the full influence of the use of an optimized percentage of Biochar (2% with respect to the weight of the cement) either as a filler in the mixture or as a substitute for cement, while guaranteeing an improvement in the strength without losing ductility. The results showed that 2 wt% of Biochar’s particles are sufficient to increase the strength and toughness of the cement and mortar composites and, in place of the cement in the mixture, can maintain the mechanical properties equal to those of the reference samples.

Polyvinyl alcohol/gelatin irradiated blends filled by lignin as green filler for antimicrobial packaging materials

ABSTRACT The prepared lignin from black liquor of bagasse was added to PVA/Gelatin blends (80/20%) at 5.0 to 20.0 phr concentrations (part per hundred volume of the blend). The prepared PVA/Gelatin-Lignin composites subjected to 5.0, 10.0, 15.0, and 25.0 kGy of gamma irradiation doses. Lignin characterised by dynamic light scattering (DLS), tensile strength (TS) and water absorption. Lignin was 712 to 1106 nm in diameter size. TS of the composites was decreased by lignin content up to 20.0 phr and increases by irradiation dose at 5.0 kGy. The water absorption was decreased and not changed greatly by time after 3 h. After 90 days of exposure in soil burial analysis, the PVA/Gelatin-Lignin blends with (15.0 and 20.0 phr) of lignin at 10.0 kGy are expected to degrade at a slow rate. Thermogravimetric analysis (TGA) indicated that lignin enhanced the thermal stability of composites. PVA/Gelatin-Lignin blends exert highly antibacterial and anti-biofilm activities against food-borne contaminants Gram-positive bacteria, Bacillus subtilis, Staphylococcus aureus, and Gram-negative bacteria; Escherichia coli, Pseudomonas aeruginosa where hydroxyl group of lignin as a phenolic compound interact with the bacterial cell causing cell membrane disruption, the infiltration of cell component and ultimately bacterial cell lysis. B. subtilis was mostly affected by lignin at 15.0phr and 10.0kGy to record (inhibition zone of 28.12 mm) and antibiofilm activity (73.6%). It indicted lignin may be used as packaging food materials.

Mechanical and thermal properties of snail shell particles-reinforced bisphenol-A bio-composites

This work was carried out to investigate the possible application of the snail shell particles (SSPs) as reinforcement which contains around 95% calcium carbonate. The main objective of this work was to study the effect of heat treatment on the mechanical and thermal properties of the epoxy/SSPs composites. The composites were investigated by mechanical testing, thermogravimetric analysis and differential scanning calorimetry. The structural and morphological properties of the bio-composites were analyzed through Fourier transform infrared spectroscopy and scanning electron microscopy. Results demonstrate that the tensile strength of the composites increased by 21, 56 and 34%, respectively, at the loading of 5, 10 and 15 wt% of SSPs and further increased by 17% for reinforcing of 10 wt% of heat-treated SSPs. The flexural strength of the composites also increased by 116, 291, 233 and 191% for loading of 5, 10, 15 wt% SSPs and 10 wt% of sintered SSPs, respectively, compared to neat epoxy. It was found that the glass transition temperature and decomposition temperature of the composites significantly improved for incorporating SSPs into the epoxy. The onset temperature of the degradation of the composites was increased maximum by 28 °C for the addition of 10 wt% of the sintered SSPs compared with the neat epoxy. The overall mechanical and thermal properties of the composites indicate that the SSPs can be a promising green filler to develop bio-composites.

Physicochemical properties of the electron beam irradiated bamboo powder and its bio-composites with PLA

The high cost and low toughness of Poly (lactic acid) (PLA) are the main drawbacks of PLA which limit its commercial applications. However, the cost of PLA can be reduced by incorporating it with various bio-based low-priced fillers. The bamboo powder (BP), lignocellulosic biomass, is promising green filler since it has high cellulose contents and no competition with food. However, its poor compatibility with the polymers reduces the mechanical properties of the resulting composite. Hence, this work investigates the electron beam irradiation pretreatment of bamboo powders. Further, the electron beam irradiated bamboo powder was blended with PLA in two different concentrations (5% and 10%) along with epoxide silane (3-Glycidoxypropyltrimethoxy silane) as a compatibilizer. The FT-IR, XRD, and TG/DTA analyses revealed that the irradiation demolishes aliphatic and aromatic moieties of bamboo powder followed by the formation of free radicals. The reduction in the intra and intermolecular hydrogen bonding among these moieties are also asserted. Moreover, mechanical and thermal properties of PLA/electron beam irradiated bamboo powder (PLA/EBP) composites are tested and obtained results have shown the improvement in the notched impact strength as well as stability in other mechanical and thermal properties. The compatibility and dispersion of the electron beam irradiated bamboo powder in the PLA matrix were analyzed by SEM studies. The hydrolytic degradation test of prepared composites was also performed.

High Density Polyethylene/Date Palm Fiber Composites: Effect of Fiber Loadings on the Dynamic Mechanical Thermal Properties

The increasing environmental issues has resulted in the trend of the use of renewable or natural source (green) fillers in the polymer composites fabrication. Among these green fillers is called natural fibers or plant fibers. One particular plant fibers that became the topic of the present work is date palm fiber (DPF). In the present work, DPF at different loadings (i.e. 0, 5, 10, 20, 30 wt%) were incorporated (as fillers) in the high density polyethylene (HDPE) matrix to fabricate HDPE/DPF composites. Further, we have investigated the effect of DPF loadings on the dynamic mechanical thermal properties of the composites. The dynamic mechanical thermal analysis (DMTA) results exhibited that the storage modulus of the composites increased with increasing DPF loadings. Additionally, all the storage modulus values of the composites were higher than the neat HDPE in all temperature ranges. For example, at temperature of 60°C, the storage modulus enhancement of the composites as compared to the neat HDPE were about 26, 76, 134, and 225% for 5, 10, 20, 30 wt% of DPF loadings, respectively. Additionally, the relationship between the DPF loadings (wt%) and temperature (°C) on the storage modulus of the HDPE/DPF composites was modeled using a logarithmic equation. Based on the data plotting between the experimental data and modeled data, the logarithmic equation was found to be fitted with the experimental data satisfactory.

Effect of Date Palm Fiber Loadings on the Mechanical Properties of High Density Polyethylene/Date Palm Fiber Composites

The trend of using natural fibers as green filler in the fabrication of polymer composites is increasing. One of these natural fibers is date palm fiber (DPF). Date palm fiber is considered as agricultural waste in certain areas, such as Middle East countries. Therefore, the utilization of this fiber in the composites fabrication is an interesting topic of research. In the current study, composites were prepared by melt blending DPF with high density polyethylene (HDPE). Five different DPF loadings were studied (i.e. 0, 5, 10, 20, 30 wt%). The effect of the DPF loadings on the mechanical properties and water absorption behavior of the composites were investigated. The tensile test result showed that tensile strengths of all the composites samples were all higher than the neat HDPE with the maximum improvement was achieved at the DPF loading of 5 wt% (i.e. DFC-5), which was about 19.23 MPa (138% higher than the neat HDPE). Whereas, the flexural test result showed that the flexural strength of the composites slightly increased compared to that of the neat HDPE only until 5 wt% DPF loading (i.e. DFC-5). Afterward, the flexural strength of the DFC-10 was equal to that of the neat HDPE, and decreasing with further increase of DPF loadings. Additionally, the water absorption test result showed that the water absorption rate and uptake of water (at equilibrium) increased with the increase of DPF loading.

Date Palm Fiber Reinforced High Density Polyethylene Composites: Effect of Fiber Loadings on the Melt Rheological Behavior

In the recent years, the trend of using renewable source (green) fillers in the composites fabrication is increasing. One of these green fillers is natural fibers, which referred to the plant fibers, such as date palm fiber (DPF). In the present work, high-density polyethylene (HDPE)/DPF composites have been prepared. Four different DPF loadings were used (i.e. 0, 5, 10, 20 wt%) to prepare the composites. The effect of DPF loadings on the melt rheological behavior of the HDPE/DPF composites were studied. The melt rheological test results showed that both of storage modulus (Gʹ) and loss modulus (Gʺ) increased with the increase of DPF loadings. Additionally, the Han plot showed an upward shift from neat HDPE (i.e. DFC-0) to DFC-20, which indicated that the melt rheological properties changed with the increase of DPF loadings. The complex viscosity |h*| of the composites samples also increased with the increase of DPF loadings. The increased was more significant at higher DPF loadings (i.e. DFC-20). Meanwhile, the Carreau-Yasuda model was found to be well fitted with the experimental data.

Effect of micro/nano white bamboo fibrils on physical characteristics of epoxy resin reinforced composites

As a green filler comprising both nano- and micro-sized fibrils, micro/nano white bamboo fibrils (MWBFs) were treated with a silane coupling agent (S-MWBFs) prior to their introduction in an epoxy resin (EP). The sequential processes of steam explosion, alkaline treatment, and micro grinding were used to prepare to MWBFs. The effects of the S-MWBFs on various characteristics of the cured EP such as compatibility, fracture toughness, morphology, mechanical property, and flame retardation were studied. The fracture toughness and mechanical characteristics of both the storage modulus and tanδ maximum increased following addition of the S-MWBFs to the EP. Notably, the fracture toughness of the EP with 0.3 wt% of S-MWBFs was 22.2% higher than that of unmodified resin. Scanning electron microscopy presented somewhat rougher surfaces with shear deformation and tortuously twisting cracks, resulting in a higher fracture toughness in S-MWBF-modified epoxy samples. However, fire testing showed that the presence of S-MWBFs increased the burning rate of the EP.

Experimental investigation of photocatalytic and photovoltaic activity of titania/rice husk crystalline nano-silica hybrid composite

As a kind of highly operative, stable photocatalysts and low‐cost, TiO2 has received significant scientific attention. However, it can only be initiated under ultraviolet light irradiation owing to its wide bandgap, weak separation efficiency of carriers and high recombination. Doping or making composites is an active method to outspread the light absorption to the visible light region. This article describes the extraction procedure of nano-silica from rice husk through a dissolution-precipitation process and producing titania-nanosilica composites by sol-gel method for photocatalytic and photovoltaic application where extracted nanosilica act as green filler to enhance the surface area of titania photocatalyst and an inhibitor of recombination. Our general plans are anticipated by passivated composite to enhance the activity of TiO2 semiconductors. This results show that the TiO2 /rice husk extracted crystalline nanosilica (RHCNS) has formed an active hybrid photocatalyst which is significant for photovoltaics application also. Large enhancement of photovoltaic parameters and rate of dye degradation of the TiO2/RHCNS composite observed which is stepping path to further development in adsorption-assisted photocatalysts under both UV and visible lights.

Cover Picture: Journal of the Chinese Chemical Society 4/2017

In this paper, a micro/mesoporous carbon‐silica materials of different carbon contents were obtained from hydrothermal treatment in acidic solution, pyrolysis and calcination on agricultural waste rice husk. After milling, the carbon‐silicas can be used as green filler to improve the thermal conductivity and storage modulus in underfill materials for green electronic packaging applications. More details will be discussed by Dr. Hong‐Ping Lin and his group on page 427–433 in this issue. image

Rice husk‐derived porous carbon/silica particles as green filler for electronic package application

ABSTRACTBio‐based porous carbon/silica particles (denoted as RH‐carbon/silica) were successfully prepared from agricultural waste rice husk by using acid‐hydrothermal treatment and pyrolysis under nitrogen condition. As green filler, the cure behavior, thermal‐mechanical properties, and thermal conductivity of the epoxy‐carbon/silica biocomposites at different filler contents (5, 9, 17, 29 wt %) were characterized. Because of superior surface properties (surface area, porosity, and silica segment) and high content of carbon component in the RH‐carbon/silica, the characteristics of the biocomposites were significantly improved with the increase of the filler content. At 29 wt % of filler content, the epoxy biocomposites exhibit lower curing temperature (148 °C), lower CTE (42 ppm/°C), higher Tg (123 °C), higher storage modulus (4059 MPa), and higher effective thermal conductivity (0.29 W/mK). In brief, the RH‐carbon/silica particles that can serve not only as reinforcing agent but also as thermal transport medium used in epoxy composite, is a green and high‐performance filler for this purpose. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44699.

Effects of spent tea leaf powder on the properties and functions of cellulose green composite films

The aim of the present work was to develop novel bio-based polymer composite films with improved tensile and thermal properties. In this work, cellulose and spent tea leaf powder (STLP) were used as the matrix and filler respectively in the preparation of biocomposite films. To make cellulose solution, cotton linters were dissolved in pre-cooled aqueous solution of 8wt.% Lithium hydroxide and 15wt.% urea. Tea is an important beverage of household and hotels and spent tea leaves form a conjugal solid waste. STLP was added to cellulose solution in 5–25wt.% of weight of cellulose. The cellulose and cellulose/STLP composite films were prepared by regeneration method using ethyl alcohol coagulation bath. The dry films were characterized by optical microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and tensile tests. The effect of STLP loading on the properties of the cellulose/STLP composite films was studied. The results indicated that the composite films had higher tensile properties and thermal stability than the cellulose matrix. The dye adsorption ability of cellulose and cellulose/STLP composites in wet form was also studied. It was observed that the composite wet films had higher dye adsorption capacity than the matrix. Results of this study indicated STLP to be a promising green filler for polymer matrices.

Preparation and Properties of Biodegradable Spent Tea Leaf Powder/Poly(Propylene Carbonate) Composite Films

The aim of the present work is to develop novel bio-based lightweight material with improved tensile and thermal properties. Spent tea leaf powder (STLP) was used as a filler to improve the tensile and thermal properties of polypropylene carbonate (PPC). Tea is an important material used in hotels and households, and spent tea leaf is a resulting solid waste. Composite films with STLP were obtained by the solution casting method. These films were characterized by optical and scanning electron microscopy, Fourier transform-infrared spectroscopy, thermogravimetric analysis, and tensile testing to examine the effect of filler content on the properties of the composites. The results showed that composite films have increased tensile strength due to enhanced interfacial adhesion between the filler and the matrix. In addition, the composite films also exhibited higher thermal degradation temperatures than pure polypropylene carbonate. The morphology results indicate that there is a good interface interaction between STLP and PPC. Results of the study reveal STLP to be a promising green filler for polymer plastics.

Synergy in epoxy nanocomposites with cellulose nanocrystals and Boehmite

The role of a stabiliser in the stiffening and strengthening of cellulose nanocrystal (CNC) filled epoxy was studied. Cetyltrimethylammonium bromide (CTAB), a cationic surfactant, and Boehmite (Boe) nanoclay were mixed with CNCs in water during processing. Boe and CTAB synergistically stiffened the CNC-epoxy composites, increasing elastic modulus by 72% over neat epoxy and 49% over unstabilised CNC-epoxy composites. Boe-treated CNC-epoxy composites exhibited a 23% increase in tensile strength over unfilled epoxy and a 63% increase over an unstabilised CNC-epoxy composite. These nanocomposites also maintained the strain-at-failure of neat epoxy and increased the storage modulus above Tg by 96%. This use of a naturally occurring alumina nanoplatelet as a synergistic stabiliser for CNCs provides a tremendous opportunity to reduce the use of surfactants in epoxy composites. This green filler system could be used to improve epoxy nanocomposites for structural components in automotive applications, construction materials and consumer products.

Solvent-free catalyst-free microwave-assisted acylation of lignin

Valorization of lignin into biomaterials requires its good compatibility with the polymeric matrix it is incorporated into. Softwood Kraft lignin was esterified with various anhydrides (acetic, propionic, butyric, methacrylic, maleic) using a solvent-free, catalyst-free, microwave-assisted method. The esterification was fast and efficient (degrees of substitution >90% after 10min). The reaction was worked up using water or ethanol as purification agent. Esterified lignins were characterized by FT-IR, GPC, quantitative 31P NMR and TGA/DSC. NMR analyses indicated that non-cyclic anhydrides reacted with both aliphatic and phenolic OH groups, while maleic anhydride reacted exclusively with aliphatic OH groups. All acylated lignins except the maleated one showed higher thermal stability than the unmodified lignin. Lignins acylated with non-cyclic anhydrides can be applied as green fillers in apolar polyolefins while maleated lignin can serve as metal adsorbent or macroreagent for the synthesis of polyesters or polyamides. We showed in this study that lignin can be modified in a fast and easy way.

Green composites of polypropylene and eggshell: Effective biofiller size reduction and dispersion by single-step processing with solid-state shear pulverization

Abstract Eggshell (ES), a waste byproduct from food processing and hatcheries, contains ∼95% calcium carbonate (CC), making it a potentially attractive, less expensive substitute for commercial CC. Past work used complex grinding–sieving and/or chemical modification steps to aid in dispersing ES in polymers such as polypropylene (PP). Both steps add to the cost and reduce the green aspect of the composite. Here, green composite materials of PP with 5–40 wt% unmodified ES shards of several centimeters in size are directly processed using continuous, single-step solid-state shear pulverization (SSSP). Electron microscopy and particle size analysis show very good dispersion with some ES particles near the nanoscale in the composite. Well-dispersed ES particles dramatically increase PP crystallization rates with a 5–7% increase in PP crystallinity. The very good dispersion leads to a major increase in Young’s modulus (87% increase relative to neat PP for 40 wt% ES) and a modest increase in hardness; composites exhibit reductions in yield strength, elongation at break, and impact properties. Mechanical and crystallization properties are equal to or better than the best literature data for PP/ES composites without chemical modification made by multi-step approaches involving melt processing. In addition, the composites exhibit high thermal degradation temperatures compared to neat PP, indicating the potential for ES to improve processing stability. Composites with 20–40 wt% ES exhibit solid-like rheological response with no crossover of shear storage and loss moduli. Nevertheless, PP/ES composites retain viscosities close to that of neat PP at shear rates experienced in melt processing. Overall, property enhancements resulting from superior dispersion of ES in PP achieved by SSSP reveal ES to be a promising green filler for thermoplastics.

Ultrasound-guided injection of the intrapelvic portion of the obturator internus in a cadaver model.

Musculoskeletal dysfunction of the pelvic floor is common. One of the intrapelvic muscles, the obturator internus (OI), can be substantially stressed during its sharply angulated exit from the pelvis. However, there may be considerable overlap between symptoms and signs arising from the OI and other potential pain generators including the levator ani in the pelvic region. Accurate diagnosis for the OI might permit more efficient treatment combined with OI-specific exercise and behavior modification. Therefore, we hypothesized that ultrasound (US)-guided needle insertion in the intrapelvic portion of the OI would be accurate when a pararectal approach is used for diagnostic and therapeutic purposes. Bilateral US-guided intramuscular injections in the pelvic area were performed using 6 fresh, nonembalmed male cadavers. When the needle was positioned in the targeted muscle, 0.5 mL of green filler was injected. After the injection procedure, each specimen was dissected to evaluate the accuracy of US-guided injection into the intrapelvic portion of the OI. Twelve injections were made into the targeted muscles in the 6 cadaveric specimens. All injections placed filler into the OI muscles just medial to the inferior pubic ramus. There was no case in which a needle passed through unintended structures, such as neurovascular structures. The newly developed US-guided pararectal approach allowed accurate insertion of a needle into the intrapelvic portion of the OI. This US-guided method facilitated a more precise approach to the intrapelvic portion of the OI and may help differentiate conditions or symptoms caused by other structures.

Cellulose nanocrystals as green fillers to improve crystallization and hydrophilic property of poly(3-hydroxybutyrate-co-3-hydroxyvalerate)

The green nanocomposites of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with various cellulose nanocrystals (CNCs) contents were prepared by solution casting method. The effects of CNCs on the crystallization behavior, spherulitic morphology, crystal structure and hydrophilic property of PHBV were studied by differential scanning calorimeter (DSC), polarized optical microscope (POM), wide-angle X-ray diffraction (WAXD) and static water contact angle measurement. It is found that the CNCs act as an effective nucleation agent for crystallization of PHBV, inducing an increase in the melt crystallization temperature of the nanocomposites. A study of the non-isothermal crystallization kinetics further illustrated that overall crystallization rate of PHBV in the nanocomposites was faster than that of neat PHBV, but exhibited a decrease in the crystallinity and the spherulite size of PHBV. Furthermore, the contact angle decreased from 60.1° for neat PHBV to 32.5° for the nanocomposites with 10% CNCs (mass fraction).