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1.
    
The effect of type and content of wood fibers on the thermal, mechanical and rheological behavior of the commercial biodegradable polyester product, Ecovio® (BASF) is analytically studied. Ecovio® is basically a blend of poly(butylene adipate‐terephthalate) copolyester (Ecoflex®, BASF) and polylactide. Three different types of wood fibers, based either on raw cellulose (Arbocel) or selected conifers (Lignocel), with varying fiber size at various weight fractions were used for this purpose. The role of these fibers on the thermomechanical performance of Ecovio® was investigated in terms of several experimental techniques including scanning electron microscopy, differential scanning calorimetry, dynamic mechanical analysis, creep, tensile testing, and water uptake at room temperature. At the low wood fiber content (20 wt %), Lignocel composite's properties are predominant compared with the Arbocel composites. It has been found, that at this wood content, an efficient compatibility between matrix and fibers is achieved, leading to superior reinforcement. This trend is completely reversed at higher filler loading, probably due to the poor interfacial adhesion between the matrix and Lignocel occurring at 30 wt %. This behavior was supported by all the experimental methods employed. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42185.  相似文献   

2.
Poly(lactic acid) (PLA) is a biodegradable, brittle, and high-cost polymer, which can be applied over structural components and green packaging. In this study, we reinforced PLA with natural cotton (10 wt %) and thermoplastic starch (TPS; 3 wt %) to obtain a biodegradable and lower cost composite. TPS was incorporated in three distinct ways: it was blended, coated, and blended and coated. In this study, we investigated the compatibilization of TPS in the improvement of matrix-reinforcement adhesion and increase in the tensile behavior without a compromise in biodegradation. The samples were investigated with thermal analysis, dynamic mechanical thermal analysis, tensile testing, scanning electron microscopy, confocal laser scanning microscopy, and hydrolytic degradation. The results show that the coupling effect was more pronounced in the PLATPS–cottonTPS (hybrid system with PLA and cotton) hybrid system. This formulation presented a higher glass-transition temperature, thermal stability, storage modulus, wettability, and ductility. The TPS addition improved the adhesion between the matrix and starched cotton fiber and retarded abiotic biodegradation. These properties will allow for green applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47490.  相似文献   

3.
    
All-cellulose composites (ACCs) were prepared by partially dissolving cellulose in the filter paper using NaOH/thiourea aqueous solution. The effects of dissolution time, thiourea ratio, and temperature on the properties of ACCs were investigated. ACCs were characterized by scanning electron microscope, attenuated total reflectance Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, and tensile tests. The results revealed that the fibers in ACCs were tightly intertwined. The crystalline form of cellulose in ACCs was transformed from type I to type I/II mixture, and the crystallinity decreased from 77.32 to 51.40%. The tensile strength of ACCs was remarkably improved to 23.16 MPa. The results confirmed ACCs had a high potential for practical applications in the packaging field.  相似文献   

4.
    
Cellulose nanocrystals (CNC) are rod-like nanoparticles extracted from cellulose. Due to their fascinating properties—renewable, biocompatible, non-toxic, biodegradable, excellent mechanical performances, high specific surface area, water dispersible, can be assemble in chiral nematic phases—CNC have shown promise in various fields, including oil recovery, polymer composites reinforcing, hydrogels, aerogels, supercapacitors, energy saving buildings, cosmetics, papermaking, coatings, liquid crystals, and waste water treatment. However, the hydrophilic surface of CNC hinders their broader applications. In this context, surface modification of CNC via polymer grafting can be used to finely tune their surficial properties and endow CNC with a variety of functionalities, such as conductivity, pH or temperature responsiveness, reactivity…In particular, surface-initiated atom transfer radical polymerization (SI-ATRP) is a powerful tool to graft various polymers with a high grafting density and controlled chain length. In this review, the precise control of grafted polymers from CNC via SI-ATRP is first discussed, including issues related to the polymer grafting density, chain length and possibility to perform an asymmetric grafting. Then, the properties and applications of CNC grafted with a variety of polymers are presented. Finally, some challenges and outlook related to the SI-ATRP method applied to the field of CNC is discussed.  相似文献   

5.
    
To find high value‐added utilization for spent mushroom substrates (SMS), a series super‐absorbent sample were prepared with SMS mass ratio between 0% and 100% based on acrylic acid plus SMS, heated with microwave. The maximum absorbency of the composite with 25% SMS ratio in water and saline corresponding to 0.3 wt % initiator is 458 and 61 g/g, respectively; the gel strength of the composite with 25% SMS is two times as high as that of the noncomposited polyacrylate. On SEM pictures, as SMS mass ratio increases the composites resin continuity was interrupted by SMS particles meanwhile some SMS particles are bare; micro‐particles of SMS uniformly dispersed in the acrylic resin forming submicroscopically homogeneous composites. IR spectra show that the composite has different chemical groups and structures from the mechanical mixture. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1098‐1103, 2013  相似文献   

6.
    
Studies were conducted on transport properties and separation performance of date pit/polysulfone composite membranes for CO2, CH4, N2, He, and H2 gases. Date seeds were obtained and processed into powder. Asymmetric flat sheet membrane was prepared by solvent casting method with 2–10 wt % date pit powder. Membrane characterization was done using high pressure gas permeation, X‐ray diffraction, thermogravimetric, and scanning electron microscope analyses. The separation performance and the plasticization resistance property were evaluated in terms of gas permeability, selectivity, and plasticization pressure, respectively. Time dependent performance properties were evaluated up to a pressure of 40 bar for 75 days. Results obtained showed the highest selectivity values of 1.54 (He/H2), 3.637 (He/N2), 2.538 (He/CO2), 2.779 (He/CH4), 3.179 (H2/N2), 3.907 (H2/CO2), 1.519 (CH4/N2), 1.650 (CO2/N2), and 1.261 (CO2/CH4) at 10 bar and 35 °C feed pressure and temperature, respectively. The resulting composite membrane showed about 39.50 and 66.94% increase in the selectivity of He/N2 and CO2/CH4, respectively, as compared to the pure polysulfone membrane. Thus, the membrane composites possess some potentials in membrane gas separation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43606.  相似文献   

7.
    
Microcrystalline cellulose (MCC) and its oxidized product dialdehyde cellulose (DAC) were introduced as the reinforcing filler in epoxidized soybean oil (ESO) thermosetting polymer. The composites comprising up to 25 wt % cellulose fillers were obtained via a solution casting. The reinforcing effects of the cellulose were evaluated by microstructure analysis, dynamic mechanical analysis, and tensile and thermal stability tests. The results showed that at the same filler concentration, DAC led to higher stretching strength, modulus, and break elongation than MCC. The 5 wt % DAC loading in ESO polymer exhibits the highest toughness and thermal stability due to the good dispersion and interfacial interaction between DAC and ESO polymer matrix. The increased storage modulus and glass transition temperature also indicate the cellulose fillers impart stiffness to the composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42488.  相似文献   

8.
    
The main objective of this study is to obtain ethylene‐vinyl acetate copolymer (EVA)/wood‐flour foams with low density (< 0.2 g/cm3) using chemical blowing agent. Stearic acid was used as a compatibilizer to improve not only the compatibility between wood‐flour and EVA but also the compatibility between moisture and EVA in this study. The effects of wood‐flour content on the density and mechanical properties of EVA/wood‐flour foams were studied. Also, the effects of content of stearic acid on the cell morphology of EVA/wood‐flour foams were investigated. The shape of EVA/wood‐flour foams with 20% wood‐flour content becomes more uniform with increasing content of stearic acid. The most stabilized shape of the foams is obtained with 5 wt % stearic acid content. The density of EVA/wood‐flour foams with 20% wood‐flour and 5 wt % stearic acid is 0.11 g/cm3. With increasing content of stearic acid, more gas remains in the EVA matrix and consequently, average cell size and density increase. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40894.  相似文献   

9.
    
Six fillers from forestry wastes (wood, bark, cones and needles from young pine trees, kraft lignin, and recycled paper sludge from industry wastes) were incorporated into polyurethane (PU)‐based foams prepared via free‐rise pouring method. Variable filler contents (1, 5, and 10 wt %) and NCO/OH ratios (0.6, 0.9, and 1.2) were investigated. A simple mixture (1:3) of castor oil and crude glycerin (byproduct from biodiesel production) was used as biobased polyol. The foam composites were investigated through spectroscopy, morphological, mechanical, and hygroscopic analyses. The addition of fillers decreased water uptake and yielded rigid PU systems with more homogenous cell structure. The 1% and 5% reinforcement wood were the most effective among the studied compositions, with better mechanical and hygroscopic performance, probably due the higher compatibility of the wood with the PU system, which promote urethanic bonds between filler and isocyanate, as indicated by wet chemical results and micrographs. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45684.  相似文献   

10.
    
Cellulose nanofibers (CNFs) have many useful properties, including high strength and low thermal expansion, and are also environmentally friendly, readily renewable, safe, and biodegradable. The focus of this study was the development of lightweight thermoplastic polymer composites with good mechanical properties based on the incorporation of CNFs that have undergone surface pretreatment with a cationic reagent. The polyamide (PA12) was mixed with surface‐treated CNFs using a twin screw extruder and the resulting pellets were injection molded. The Izod impact strength without notch of CNF‐based composites exceeded that of composites incorporating organophilic montmorillonite (OMMT), a representative nanocomposite material. When the Izod impact test without notch, the impact hammer was stopped by the specimen with incorporation of surface treated CNF. Furthermore, the bending modulus and strength were equal to or greater than that of OMMT composites. The heat distortion temperature was improved as 33°C from neat PA12, and moreover improved as 29°C from OMMT composites. Cationic pretreatment of the CNF surfaces was found to increase the dispersion of the fibers and also to greatly improve the mechanical and thermal properties of the composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40920.  相似文献   

11.
    
Cellulose-based aerogels have been regarded as potential adsorbent materials because of their unique structural features and chemical stability. Herein, we prepared the composite aerogels containing cellulose and N,N′-methylene bisacrylamide (MBA) using N-methylmorpholine-N-oxide (NMMO) as a green solvent via a freeze-drying process. Owing to the strong chemical interaction between CC bonds of MBA and the functional groups of cellulose, as-obtained cellulose/MBA aerogels present favorable MBA-induced thermal/mechanical stable three-dimensional network structure, in which the abundant macroporous structure, low density and high porosity lead to a significantly enhanced adsorption capacity (260.31 mg∙g−1) toward congo red dye in aqueous solution compared with the pure cellulose aerogels. Moreover, the effect of the cellulose concentration and cross-linking degree on the morphology and adsorption properties for cellulose/MBA aerogels was systematically investigated. This present work provides a low-cost and environmental-friendly synthesis method for designing the functionalization of cellulose-based aerogel, which may be achieved the advanced performance in wastewater treatment.  相似文献   

12.
    
A cauliflower-like ternary nanocomposite of poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide (PEDOT/NCC/MnO2) was synthesized using one-step electropolymerization technique. The effect of manganese (Mn) concentration on the supercapacitive performance was investigated. The structural and morphology studies were conducted using field emission scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The morphology of ternary nanocomposite at an optimized concentration of Mn resembles the cauliflower-like structure. The two-electrode electrochemical analysis of a ternary nanocomposite PEDOT/NCC/MnO2 exhibited a higher specific capacitance of 144.69 F/g at 25 mV/s in 1.0 M potassium chloride compared to PEDOT/NCC(63.57 F/g). PEDOT/NCC/MnO2 ternary nanocomposite was able to deliver a specific power of 494.9 W/kg and 10.3 Wh/kg of specific energy at 1 A g−1 and retained 83% of initial capacitance after 2,000 cycles. These promising results from the incorporation of Mn displayed great prospective in developing PEDOT/NCC/MnO2 as an electrode material for supercapacitor.  相似文献   

13.
    
Cellulose nanofibers (CNFs) were isolated from kenaf fibers and wheat straw by formic acid (FA)/acetic acid (AA), peroxyformic acid (PFA)/peroxyacetic acid (PAA), hydrogen peroxide (H2O2) treatment; and subsequently through ball milling treatment. Characterization of extracted cellulose and cellulose nanofibers was carried out through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). TEM images showed that extracted cellulose nanofibers had diameter in the range of 8–100 nm. FTIR and XRD results implied that hemicellulose and lignin were mostly removed from lignocellulosic biomass with an increase in crystallinity, and isolation of cellulose nanofibers was successful. The TGA results showed that decomposition temperature of cellulose nanofibers increased by about 27°C when compared with that of untreated lignocellulosic biomass. No significant change was observed in the decomposition temperature of bleached celluloses after ball milling. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42990.  相似文献   

14.
    
The present work describes the preparation of polypropylene composites reinforced with cotton fibers, which were obtained from textile waste. The cellulosic fibers were bleached and then chemically modified on the surface using acetylation or silanization methods. Fourier transform infrared spectroscopy analysis and energy dispersive X‐ray spectroscopy confirmed the efficiency of both treatments. Results of thermal degradation by thermogravimetric analysis (TGA) of treated fibers indicated that the acetylated ones decreased thermal stability while the silanized fibers increased this property. The influence of the chemical modifications and fibers content in polypropylene‐based composites was studied by thermomechanical and mechanical properties (dynamic mechanical analysis and tensile tests) and thermal analyses (TGA and differential scanning calorimetry). The results showed that the addition of the obtained cellulose fibers in polypropylene caused increase of storage and Young's moduli, along with stress at break. Moreover, scanning electronic microscopy micrographs of cryofractured surfaces revealed stronger adhesion between fiber and matrix in the composites reinforced with the modified fibers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45060.  相似文献   

15.
    
In view of the current public concern about microplastics, biodegradability of 3D-printed polymeric materials is an important issue. In this work, we studied the effects of soil-burial biodegradation treatment on wood-polylactic acid (PLA) blends with three different thermoplastic starch (TPS) contents (i.e., 0, 10, and 20 wt%). The wood-PLA-TPS composites were 3D-printed through the fused deposition modeling technique. The use of TPS led to reduced mechanical properties and thermal stability of the composites. Biodeterioration of the composites was clearly observed for the composite with high TPS content after the soil burial test. Thermal decomposition temperature, activation energy, and degree of crystallinity of biodegradation treated composites increased for composites with higher TPS content. The observed behavior was due to decomposed TPS and wood in the composites from biodegradation treatment, resulting in increase in the relative PLA content level. Also, the weight loss percentage of composites increased from 3.2% to 18.5% after the soil burial test as the TPS content in the composites increased from 0 to 20 wt%. The presence of TPS and wood helped improve the biodegradation of the 3D printed PLA composites, while PLA itself is not easily bio-degraded.  相似文献   

16.
    
One of the most prevalent cancers affecting women globally is breast cancer. Consequently, the development of cost-effective and low-risk treatment options remains a critical pursuit. This study describes the synthesis via water-in-oil-in-water (W/O/W) of a pH-responsive nanocarrier for curcumin delivery, a promising anticancer drug. The nanocarrier comprises carboxymethyl starch (CMS), polyethylene glycol (PEG), and gamma alumina (γ-Al2O3) nanoparticles. The molecular interactions between the nanocomposite components, its crystalline structure, surface morphology, size distribution, and surface charge were assessed via Fourier-transformed infrared (FTIR) spectroscopy, field emission-scanning electron microscopy (FE-SEM), x-ray diffraction (XRD), dynamic light scattering (DLS) and zeta potential, respectively. The nanocarrier showed a size ranging from 150 to 280 nm, zeta potential of +35.4 mV, drug loading of 47% and an encapsulation efficiency of 87%, which are among the maximum values reported to date for curcumin nanocarriers. A gradual drug release was observed, with 51% and 90% released after 72 h at pH 7.4 and 5.4, respectively, which corroborates the pH-sensitivity of the nanocarrier. The cytotoxic effects of the curcumin-loaded nanocomposite on MCF-7 breast cancer cells and normal cells were investigated using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and flow cytometry. The results demonstrated that loading curcumin onto the hydrogel significantly enhances its penetration into MCF-7 cells. Overall, this novel nanocomposite offers a promising approach for curcumin delivery in breast cancer treatment.  相似文献   

17.
    
In the present study, a new, green, and biodegradable molecularly imprinted polymer (MIP) based on modified cellulose is introduced for the drug furosemide. First, microcrystalline cellulose was converted into cellulose acrylate (CA). Then the prepared CA underwent self‐crosslinking in the drug preassembly solution. The preassembly solution of the drug was also prepared using furosemide as the template molecule and acrylamide as the functional monomer in an aqueous medium. The results obtained from the binding and selectivity studies indicate the successful preparation of the CA‐based MIP (CA‐MIP) in aqueous solution. In the final step, an in vitro release study of furosemide from the synthesized polymers was carried out in a pH = 7.41 phosphate‐buffered saline solution at 37 °C. The drug release profiles showed that the release rate of the CA‐MIP is more controlled than that of the corresponding nonimprinted polymer, especially at the early stages of release. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45581.  相似文献   

18.
    
Artificial wood films containing cellulose, xylan, and lignin were easily prepared by the dissolution of wood components in 1‐ethyl‐3‐methylimidazolium acetate followed by reconstitution with distilled water. The composition and characteristics of wood films were highly controllable and predictable through the variation of the concentration of each component in the wood solution. The water vapor solubility of the wood films was increased when the xylan content was increased and the content of lignin was decreased. The biodegradability of the artificial wood films was investigated with cellulase from Trichoderma viride. The relative degradability of the wood film prepared with 5% cellulose and 5% lignin was 42%, whereas that of the wood film made with 5% cellulose and 5% xylan was 189%. The biodegradability of cellulose in the wood films correlated well with the content of xylan and lignin, and it was enhanced when the xylan content was increased and the content of lignin was decreased. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42109.  相似文献   

19.
    
As the formaldehyde is one of the main indoor pollutants, the purpose of this study is to effectively remove indoor formaldehyde pollution by using environmentally friendly 3D printing ornaments. The wood 3D printing filaments cellulose/polylactic acid composite (Cellu/P) was selected as the starting material, and 3-aminopropyltriethoxysilane (APTES) was used for chemical modification to obtain a series of cellulose composite materials with amino groups. The modified composite materials (APTES@Cellu/P) were characterized by Fourier transform infrared, X-ray diffraction, scanning electron microscope, energy dispersive spectroscopy, thermogravimetric analysis, and mechanical tests, and a formaldehyde removal experiment was performed. The feasibility of 3D printing was evaluated, and the process of 3D printing-functionalized customized ornaments was proposed, and then a school emblem was used for modeling, printing, and surface modification. Compared with the commercially traditional activated carbon, 3D printing-customized ornaments of APTES@Cellu/P material has a better formaldehyde removal effect, and can even avoid the secondary pollution that is common to the activated carbon.  相似文献   

20.
    
In this study, ethylene‐vinyl alcohol copolymer (EVOH) nanocomposites were prepared by melt compounding both plant cellulose nanowhiskers (CNW) and bacterial cellulose nanowhiskers (BCNW) as nanofillers. Electrospinning and a “dissolution precipitation” method were used as strategies for the incorporation of CNW in EVOH before melt compounding with the aim of enhancing the degree of dispersion of the nanocrystals when compared with direct melt‐mixing of the freeze‐dried product with the polymer. As revealed by morphological characterization, the proposed preincorporation methods led to a significant improvement in the dispersion of the nanofiller in the final nanocomposite films. Furthermore, it was possible to incorporate concentrations as high as 4 wt % BCNW without causing significant agglomeration of the nanofiller, whereas increasing the CNW concentration up to 3 wt % induced agglomeration. Finally, DSC studies indicated that the crystalline content was significantly reduced when the incorporation method led to a poor dispersion of the nanocrystals, whereas high‐nanofiller dispersion resulted in thermal properties similar to those of the neat EVOH. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

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