Fabricating durable,fluoride‐free,water repellency cotton fabrics with CPDMS

The demand for fluoride‐free and durable hydrophobic cotton fabric is dramatically increasing due to environmental and human safety concerns. The current approach to produce water repellent cotton fabrics is applying fluorocarbon compounds in topical treatments. However, the fluorocarbons employed in the water repellent treatments on cotton fabrics have environmental concerns and environmentally friendly technologies are desperately sought. Herein, we report a new approach of fabricating water repellent cotton fabrics with proper washing durability by using poly{dimethylsiloxane‐co‐[2‐(3,4‐epoxycyclohexyl)ethyl]methylsiloxane} (CPDMS) as a hydrophobic agent. Benefiting from formation of robust ether bonds between CPDMS and celluloses, the cotton fabrics could gain promising durability for daily laundry. The resultant cotton fabrics demonstrated simultaneously desired waterproofness (hydrostatic pressure up to 22 mbar), durability (hydrostatic pressure stabled at 12 mbar after five laundry cycles), and breathability. Moreover, the CPDMS modified cotton fabrics also exhibited robust physical property with tensile strength retention up to 73%. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46396.     

Melt compounded nanocomposites with semi‐interpenetrated network structure based on natural rubber,polyethylene, and carrot nanofibers

The present study deals with the processing and characterization of cellulose nanocomposites natural rubber (NR), low‐density polyethylene (LDPE) reinforced with carrot nanofibers (CNF) with the semi‐interpenetrated network (S‐IPN) structure. The nanocomposites were compounded using a co‐rotating twin‐screw extruder where a master‐batch of NR and CNF was fed to the LDPE melt, and the NR phase was crosslinked with dicumyl peroxide. The prepared S‐IPN nanocomposites exhibited a significant improvement in tensile modulus and yield strength with 5 wt % CNF content. These improvements are due to a better phase dispersion in the S‐IPN nanocomposites compared with the normal blend materials, as demonstrated by optical microscopy, electron microscopy and ultraviolet–visible spectroscopy. The S‐IPN nanocomposite also displayed an improved crystallinity and higher thermal resistance compared with NR, CNF, and the normal blend materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45961.     

从感受性角度探讨他心问题

他心问题自提出以来就引起许多学者的关注,对于能否获知他心这一问题至今没有明确的答案.本文在维特根斯坦、罗素及斯特劳森对于他心问题的不同解答的基础上,从感受性角度出发探讨他心问题,认为关于他心知识的获得是可能的,但从根本上理解他心又是不可能的.     

Bio‐sorbents from cassava waste biomass and its performance in removal of Pb2+ from aqueous solution

Cassava xanthogenate and their derivatives, as adsorbents to remove Pb²⁺ from aqueous solution, are studied based upon orthogonal factorial design. The structural and thermal properties, adsorption performance as well as equilibrium‐kinetics are comprehensively investigated with multiple tools, such as Fourier transform infrared spectroscopy, thermal gravimetric analysis (TGA), and UV–visible spectrum technique. The influence of multiple parameters, including initial Pb²⁺ concentrations, compositions, pH values, and temperatures, on the adsorption performance is emphasized. The crosslinked cassava xanthogenate serves as an effective bio‐sorbent to remove Pb ions from aqueous solution, allowing regeneration in dilute acid solution. The findings in this study are beneficial for the development of adsorbents from cassava waste biomass and may contribute to environment recovery in “nature‐to‐nature” manner. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39780.     

Extraction of fibers from saccharum munja grass and its application in composites

With growing environmental awareness, ecological concerns and new legislations, natural fiber‐reinforced plastic composites have received increasing attention during the recent decades. The natural fiber composites have many advantages over traditional glass fiber composites, including lower cost, lighter weight, environmental friendliness, and recyclability. This article reports the findings of the studies done on a new fiber, hitherto unexplored, extracted from Saccharum munja grass. The extracted fibers were further treated using sodium hydroxide to improve its performance in composites. Both treated and untreated fiber‐reinforced composites were prepared by hand lay‐up process using unsaturated polyester resin. Mechanical properties and thermal behavior of the composites were evaluated. The improvement in properties was found for alkali‐treated fiber composites. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40829.     

Cellulose nanofibers prepared from TEMPO‐oxidation of kraft pulp and its flocculation effect on kaolin clay

Cellulose nanofibers were prepared using TEMPO/NaBr/NaClO oxidation of kraft pulp and successive ultrasonic treatment, and the properties were characterized by conductimetric titration, X‐ray diffraction, and atomic force microscopy. The resulting product was then applied as an anionic microparticle to constitute a microparticulate system with cationic polyacrylamide (CPAM), to induce the flocculation of the kaolin clay suspension. The flocculation effect was evaluated by determining the relative turbidity of clay suspension. The results showed that the obtained cellulose nanofibers had cellulose I structure with higher crystallinity than that of the kraft pulp, and their cross‐sectional dimension was in the range of 3–5 nm. They had more negative zeta potential at neutral and alkaline conditions. It was found that the microparticulate system showed high flocculation effect on kaolin clay at a very low level of nanofiber addition, and a high shear level after CPAM addition was helpful for the flocculation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40450.     

Study on the preparation and mechanical properties of injection‐moulded wood‐based plastics

The objectives of this study were to prepare injection‐moulded wood‐based plastics and to characterize their mechanical properties. Injection‐moulded wood‐based plastics with satisfactory flexural (65.7 MPa) and tensile strengths (30.1 MPa) were successfully obtained through a simple reaction of mulberry branch meal with phthalic anhydride (PA) in 1‐methylimidazole under mild condition. The X‐ ray diffraction results indicated complete disruption of the crystallinity of cellulose because the pattern obtained for esterified fiber was almost a straight line without any peaks. The peaks in the Fourier transform infrared spectroscopy spectra (1738 and 748 cm^?1) and NMR spectra (173.3 and 133.5 ppm) indicated the attachment of 0‐carboxybenzoyl groups onto the wood fibers via ester bonds. The differential scanning calorimetry curves showed that the glass transition temperature decreased with increasing weight percentage gain (WPG). The derivative thermogravimetric analysis curves indicated that esterified wood fiber was less thermally stable than the untreated fiber and that the component tends to be homogeneous with increasing WPG. Scanning electron microscope revealed that the fractured surfaces of most samples were smooth and uniform but that high temperature and less PA dosage could lead to the appearance of holes and cracks. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41376.     

Torrefied biomass‐polypropylene composites

Torrefied almond shells and wood chips were incorporated into polypropylene as fillers to produce torrefied biomass‐polymer composites. The composites were prepared by extrusion and injection molding. Response surface methodology was used to examine the effects of filler concentration, filler size, and lignin factor (relative lignin to cellulose concentration) on the material properties of the composites. The heat distortion temperatures, thermal properties, and tensile properties of the composites were characterized by thermomechanical analysis, differential scanning calorimetry, and tensile tests, respectively. The torrefied biomass composites had heat distortion temperatures of 8–24°C higher than that of neat polypropylene. This was due to the torrefied biomass restricting mobility of polypropylene chains, leading to higher temperatures for deformation. The incorporation of torrefied biomass generally resulted in an increase in glass transition temperature, but did not affect melting temperature. Also, the composites had lower tensile strength and elongation at break values than those of neat polypropylene, indicating weak adhesion between torrefied biomass and polypropylene. However, scanning electron microscopy results did indicate some adhesion between torrefied biomass and polypropylene. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41582.     

Modifying biodegradable plastics with additives based on condensed tannin esters

Condensed tannins derived from Pinus radiata bark have been esterified and added to biodegradable plastics as extrusion compounded functional plastic additives. The presence of longer alkyl chain hexanoate esters promoted tannin miscibility in the commercial polyesters Bionolle? and Biopol? whereas short chain acetate esters tended to remain as discrete domains, acting as fillers in the processed plastics. In the aliphatic polyester Bionolle the presence of tannin esters at typical plastic additive loadings did not alter plastic mechanical properties whereas at 5% content in Biopol the tannin‐additives reduced both flexural and tensile properties. Similarly tannin esters do not alter the melt or glass transition temperatures of the polyesters, but tannin hexanoate at 5% can influence the crystallization temperatures. Artificially aging plastics realized the functionality these plant extracts can impart to plastics in acting to reduce ultraviolet (UV)‐induced plastic degradation. Results indicate the tannin‐additives likely provide a stabilising role through inhibiting UV penetration into the plastic, with color analysis suggesting the tannin moiety itself was sacrificial and preferentially degrading. The imparted UV stability was linked to the dissolution of tannin esters in the plastic with longer chain esters providing greater protection against UV degradation. Tannin esters showed potential as functional additives for biodegradable polymers enhancing the UV stability of the plastic. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41626.     

Lime mud CaCO3 for use as a filler material in papermaking: Impact of its preflocculation with cationic polyacrylamide

Cationic polyacrylamide with different molecular weights were used to preflocculate the lime mud (LM) before it was added to the paper stock for handsheet preparation. The particle sizes, ζ potential, and morphology of the unpreflocculated and resulting preflocculated LM were studied. We found that high‐molecular‐weight cationic polyacrylamide (H‐CPAM) led to larger LM flocs with a more positive ζ potential. The scanning electron microscopy images indicated that the morphological structure of the filler hardly changed during the preflocculation process. The effects of the preflocculation on the filler retention and paper properties were also investigated. The results show that the handsheets filled with preflocculated LM had better hydrophobicity and strength properties compared to handsheets filled with unpreflocculated LM, especially for H‐CPAM‐preflocculated LM. The paper formation was also improved, and the optical properties nearly remained the same. In addition, the LM preflocculated with H‐CPAM had the highest filler retention. At a filler loading of 30%, the filler retention of the H‐CPAM‐preflocculated LM was higher than 86; it was less than 82.5% in other cases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41640.