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Novel cellulose based flocculants C-g-P (DMC) with various chain architectures are synthesized through a situ graft copolymerization. The cationic ammonium chloride group (DMC) is grafted onto cellulose by two separate inverse emulsion polymerization with γ-methacryloxypropyl trimethoxy silane (KH-570) and double bond addition reactions, which is a new and simple method to employ KH-570 as a bridge for the connection of cellulose matrix and DMC group. The effects of pH, flocculant dose, standing time on turbidity of kaolin suspensions and particle sizes have been studied systematically. In addition, the response surface methodology (RSM) study confirms that PAC and C-g-P (DMC) have synergy in turbidity removal with a higher removal efficiency of 98.32%. Moreover, C-g-P (DMC) 1has higher removal efficiency with 96.5% at a low dosage of 0.6 mg L−1and better floc properties than C-g-P (DMC) 2and C-g-P (DMC) 3, suggesting that the length and quantity of cationic branch chains play a crucial role in Kaolin flocculation due to their dramatically enhanced bridging effects.

Poly (butylenesadipate-co-terephalate) (PBAT) was modified by melt grafting glycidyl methacrylate (GMA) in the presence of benzoyl peroxide (BPO) in a Haake mixer; and the various properties of blends of PBAT/thermoplastic starch (TPS) using GMA-grafted PBAT (PBAT-g-GMA) as compatibilizer were investigated. The blends comprising TPS content ranged from 20wt% to 50wt%. Thermal properties and thermal stability were characterized with DSC and TGA, respectively. The morphologic results indicated that the interfacial adhesion of PBAT/TPS blends was improved by PBAT-g-GMA. In comparison with the uncompatibilized blends, the tensile properties of compatibilized blends were significantly enhanced, particularly at a high content of TPS (i.e., 40wt% and 50wt%).

In this work, the innovative starch microcapsules enclosed with hydrophobic carnauba wax were developed, which were applied to the modification of cellulose fibers, thus increasing the water resistance of paper by reducing water vapor transmission rate (WVTR). Carnauba wax being encapsulated by crosslinking starch was confirmed by thermogravimetric analysis. The sizes of carnauba wax-starch microcapsules depended on the weight ratio (R) of starch to carnauba wax and concentration of crosslinker. The best performance on water vapor barrier of the paper was achieved by the fibers treated with the microcapsules of larger size. The lowest WVTR was given by the handsheet treated by wet-end addition with carnauba wax-starch microcapsules at Rstarch/ carnauba wax=5%, and R crosslinker/ carnauba wax=50%, and had a value of 348 g/m2day, a 70% drop from untreated original paper which has a WVTR value of 1176 g/m2day.

Two approaches of improving the toughness of polypropylene (PP)-based composites reinforced by natural cellulose fibers were developed. The surface modification of cellulose fibrils (CMF) or fiber by either in-situ grafting polymerization of butyl acrylate (BA) on CMF surface via an atom transfer radical polymerization (ATRP) or adsorbing the cationic polymeric latex with core-shell structure on fiber surfaces was performed; and resulting fibers or CMF were used as reinforments in an attempt to enhance the toughness of the PP-based composites. The results of mechanical properties indicated that the flexure, tensile, and impact strengths of the CMF-g-PBA reinforced composites were all improved. The cellulose fibres treated by cationic latex also showed the same trend. The optimal dosage of latex for hydrophobic-modifying fibers was also identified.

In this work polyvinyl alcohol (PVA) was modified via grafting or coupling with the guanidine-based antimicrobial polymer using epichlorohydrin as a crosslinking agent. The resulting polymer was tested for its charge density and inhibition against E.coli. The modified PVA adsorbed onto cellulose fibres via electrostatic association; thus resulting in the hand-sheets (or paper) with improved antimicrobial activity. As a further extension of this work, the temperature-responsive antimicrobial polymers were prepared based on acetalyzed PVA (APVA) grafted with guanidine-based polymer chains. In conjunction with anionic APVA copolymer (APVA copolymerized with sodium acrylate), the cationic and responsive APVA formed a unique antimicrobial polymer system via layer by layer (LbL) assembly, which could adsorb on fibre surfaces and be incorporated into cellulose fibre networks, leading to the functionalizing of cellulose fibres. The lower critical solution temperature (LCST) of APVA copolymer could be tailored by controlling the degrees of acetalysis (DA) and co-monomer ratios. AFM images obtained to reveal the roughness of the surfaces; while the antimicrobial test proved that cellulose fiber assembled with APVA-based multilayers exhibited excellent antimicrobial activity against E.coli.

Hydrophobic modification of cellulose fibres was conducted by plasma-induced polymer grafting in an attempt to increase the hydrophobicity of paper. Two hydrophobic monomers, i.e., butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA) were grafted on cellulose fibres, induced by atmospheric cold plasma. Various influencing factors associated with the plasma-induced grafting were investigated, including the contact time and reaction temperature with monomers, and the dosage of monomers. Contact-angle measurement, infrared spectrum (IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used to ascertain the occurrence of the grafting. The results showed that the hydrophobic property of the modified paper sheet was improved significantly after the plasma-induced grafting. The water contact angle on the surface of the paper reached up to higher than125°.

Due to its buffer property, activity, absorbability and safety, magnesium hydroxide is widely used in environmental protection, pharmaceutics, pulp and paper industry, and as flame-retardant filling in composite materials. The hydrothermal synthesis of magnesium hydroxide at low temperature (< 100?) needs only simple equipment and is environmentally friendly and energy-saving, so the process is promising and easy for industrialization. In this study, we have investigated the effects of hexamethylenetetramine and ammonia additives on the hydrating synthesis of superfine Mg (OH)2 particles at 70?. Mg (OH)2 particles formed were of platelet shape and the mean diameter was approximately 200nm. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were applied to characterize the crystal phase, size distribution and morphology of the crystal particles. Different morphologies of Mg (OH)2 particles were formed in hexamethylenetetramine and ammonia solutions. The generation velocity of hydroxyl (OH-) was found to play an important role in the distribution and morphology of Mg (OH)2 particles.

In this paper, two guanidine derivative polymers were synthesized by reacting polyhexamethylene guanidine hydrochloride (PHGH) with starch and epichlorohydrin (EP) respectively and used as potential functional additives in papermaking. The molecular structure of the guanidine derivative polymers were characterized by FTIR and 2D NMR. PHGH- modified starches exhibited high antimicrobial activities against E. coli and the growth inhibition reached almost 100% in the presence of 1.0 wt.% PHGH in wood fibers. UV260 absorption was applied to reveal the dynamic antimicrobial process of guanidine derivative polymer obtained with PHGH and EP. Results showed that most of bacteria was deactivated within a few mins and the intracellular components were leaked when the concentration of the guanidine derivative polymer were higher than the minimum inhibitory concentration (MIC).

A thermal-responsive polymer was prepared by partially acetalyzing poly(vinyl alcohol) (PVA). The completely reversible polymer aggregation and dissolution occur above and below a low critical solution temperature (LCST) for the aqueous solution of the modified PVA. The partially acetalized PVA (APVA) with higher molecular weight and higher degree of acetalysis exhibited a lower LCST transition and was used as an anionic polymer for polymer complexation. Water-soluble polymer, cationic polyhexamethylene guanidine hydrochloride (CPHGH) with antimicrobial property, was also prepared. In conjunction with APVA, CPHGH created the unique antimicrobial polymer multilayers on the surfaces of rayon fibres via layer by layer (LbL) assembly. AFM images revealed that the particles generated by multilayers became larger after the material was treated at 60°C; while the roughness of the surfaces was increased as the layer number increased and then decreased. Moreover, antimicrobial tests also demonstrated that the rayon fiber assembled with (CPHGH/APVA) multilayers exhibited higher antimicrobial activity against E. coli and s. aureus.