Polyvinyl alcohol reinforcement

J. A. Uddin, J. Araki, and Y. Cotoh, Toward Strong green nanocomposites Polyvinyl alcohol reinforced with extremely oriented cellulose whiskers. Biomacromolecules 12(3), 617-624(2011). 

The actual experimental moduli of the polymer materials are usually about only % of their theoretical values [1], while the calculated theoretical moduli of many polymer materials are comparable to that of metal or fiber reinforced composites, for instance, the crystalline polyethylene (PE) and polyvinyl alcohol have their calculated Young s moduli in the range of 200-300 GPa, surpassing the normal steel modulus of 200 GPa. This has been attributed to the limitations of the folded-chain structures, the disordered alignment of molecular chains, and other defects existing in crystalline polymers under normal processing conditions. 

In the homogenous mixture of Starch and Polyvinyl alcohol (PVA), 30 % of plasticizer was mixed to make Pure blend. Then 10 % cellulose was mixed into above mixture followed by removal of extra water gave Cellulose-Reinforced starch-PVA blends. The different proportions of Fly ash were mixed into mixture of Cellulose-Reinforced starch-PVA blends to get various fly ash inserted Cellulose-Reinforced starch-PVA blends. Solubility, swelling behaviour and water absorption studies of Fly ash blends were measured at different time intervals at relative humidity of 50-55%. The insertion of Cellulose into starch-PVA blend decreases the solubility of blends due to the hydrophobicity of cellulose, but the solubility further increases by insertion of Fly ash into starch-PVA matrix that indicating the mechanical stability enhancement of blends. The water absorption behaviour of fly ash blends increases rapidly upto 150 min and then no change. The optimum concentration of Fly ash into Cellulose-Reinforced starch-PVA blend was 4%. 

The effect of polymer-filler interaction on solvent swelling and dynamic mechanical properties of the sol-gel-derived acrylic rubber (ACM)/silica, epoxi-dized natural rubber (ENR)/silica, and polyvinyl alcohol (PVA)/silica hybrid nanocomposites was described by Bandyopadhyay et al. [27]. Theoretical delineation of the reinforcing mechanism of polymer-layered silicate nanocomposites has been attempted by some authors while studying the micromechanics of the intercalated or exfoliated PNCs [28-31]. Wu et al. [32] verified the modulus reinforcement of rubber/clay nanocomposites using composite theories based on Guth, Halpin-Tsai, and the modified Halpin-Tsai equations. On introduction of a modulus reduction factor (MRF) for the platelet-like fillers, the predicted moduli were found to be closer to the experimental measurements. 

A new high impact blend of PET and polybutene (Valox CT) is also available. - The melt viscosity of blends of PET and nylon-66 has been reduced by the addition of polyvinyl alcohol. Self reinforcing PET has been produced by the addition of p-hydroxybenzoic acid which forms liquid crystals in the composite. 

When the coloring of latex-modified mortar and concrete is required, alkali-resistant, weatherproof pigments are used. Furthermore, it is important that the pigments do not obstruct the stability of polymer latexes and the hydration of cements. Alkali-resistant glass, steel, polyamide, polypropylene, polyvinyl alcohol (poval), aramid and carbon fibers are employed as mixable reinforcements. Reinforcing bars for ordinary cement concrete are also used for the reinforcement of the latex-modified concrete. 

Where cracks in foams are sufficiently large to weaken the structure of an artwork, a filler which provides reinforcement as well as improving appearance may be necessary to minimize future damage. A relief by Ferdinand Spindel, which comprised a foam sheet (1.5 cm thick) folded irregularly and nailed to a chipboard base, exhibited large cracks. Implants of new polyurethane ester foam with the same cell diameter as the original were cut to size, secured in place with a polyvinyl alcohol dispersion and painted red to match the original surfaces. The structural fill is reversible (van Oosten, 1999). 

Zimmermann et al. [134] have used cellulose fibrils obtained from sulphite wood pulp to reinforce water soluble polymers such as polyvinyl alcohol (PVA) and hydroxypropyl cellulose (HPC). The mechanical properties of these nanocomposites were measured by tensile tests showing that the addition of fibrils increase the modulus of elasticity (E) up to three times and the tensile strength up to five times compared to the raw polymer. Zimmermann et al. [135] have determined the E values and the hardness of cellulose/HPC nanocomposites using nanoindentation technique. The results showed that the E values measured by nanoindentation were from two to three times higher than the E values measured by means of tensile tests. Stauss et al. [136] have explained that differences between tensile test and indentation results are due to the fact that they do not test the same material volumes and regions. The large volume used in tensile test includes defects such as pores, cracks and impurities. 

Roohani, M., Habibi, Y., Belgacem, N.M., Ebrahim, G., Karimi, A.N., Dufresne, A. Cellulose whiskers reinforced polyvinyl alcohol copolymers nanocomposites. Eur. Polym. J. 44, 2489-2498 (2008)... 

Cheng, Q. Wang, S. Rials, T. Lee, S. (2007a). Physical and mechanical properties of polyvinyl alcohol and polypropylene composite materials reinforced with fibril aggregates isolated from regenerated cellulose fibers. Cellulose, Vol. 14, pp. 593-602, ISSN 0969-0239... 

Molecular-level dispersion of graphene into polyvinyl alcohol) and effective reinforcement of their nanocomposites. Adv. FuncL... 

The discovery CNs by lijima in 1991 [1] captured the attention of researchers in a wide range of areas. The CNTs have high tensile strength (100 GPa), high Yotmg s modulus (0.6 TPa) [12] and exceptional electrical conductivity (5000 S/cm) [13]. CNTs have been used as a reinforcement filler in polyvinyl alcohol [14], epoxy [15],poly-(propionylethylenimine-co-ethylenimine) [16] host matrices. The addition of CNTs has also been foimd to increase the strength and condnctivity of polypyrrole (PPy) [17]. The addition of CNTs to polyoctylthiophene (POT) has been shown to enhance the conductivity by 5 orders of magnitude with an 11% (w/w) percolation threshold... 

Roohani M, Habibi Y, Belgacem NM, Ebrahim G, Karimi AN, Dufresne A et al (2008) Cellulose whiskers reinforced polyvinyl alcohol copolymers nanocomposites. J Eur Polym 44 2489-2498... 

Ljungberg N, Cavaille J-Y, Heux L (2006) Nanocomposites of isotactic polypropylene reinforced with rod-like cellulose whiskers. Polymer 47 6285-6292 Lu Y, Weng L, Cao X (2005) Biocomposites of plasticized starch reinforced with cellulose crystallites from cottonseed linter. Macromol Biosci 5 1101-1107 Lu J, Wang T, Drzal LT (2008) Preparation and properties of microfibrillated cellulose polyvinyl alcohol composite materials. Compos Part A 39A 738-746 Magalhaes WLE, Cao X, Lucia LA (2009) Cellulose nanocrystals/cellulose core-in-shell nanocomposite assemblies. Langmuir. doi 10.1021Aa901928j Malainine ME, Mahrouz M, Dufresne A (2005) Thermoplastic nanocomposites based on cellulose microfibrils from Opuntiaficus-indica parenchyma cell. Compos Sci Technol 65 1520-1526 Marchessault RH, Sundararajan PR (1983) Cellulose. In Aspinall GO (ed) The polysaccharides. Academic, New York... 

Roohani M, Habibi Y, Belgacem NM et al (2008) Cellulose whiskers reinforced polyvinyl alcohol copol Tners nanocomposites. Eur Polym J 44 2489-2498 Ruiz MM, Cavaille JY, Dufresne A et al (2000) Processing and characterization of new thermoset nanocomposites based on cellulose whiskers. Compos Interface 7 117-131 Ruiz MM, Cavaille JY, Dufresne A et al (2001) New waterborne epoxy coatings based on cellulose nanofillers. Macromol Symp 16 211-222 Saito T, Nishiyama Y, Putaux JL et al (2006) Homogeneous suspensions of individualized microfibrils from TEMPO-catalyzed oxidation of native cellulose. Biomacromolecules 7 1687-1691... 

The complex formed by amylose with the complexing agent is usually crystalline, characterized by an amylose single helix around the complexing pol3mer [32]. Amylopectin does not interact with the complexing polymer, remaining in the amorphous phase. Starch can also be blended with polyvinyl alcohol (PVOH), for the production of foamed products, such as trays for food. Starch esters reinforced with natural fibers exhibit properties similar to those of polystyrene (PS). 

Electrical conductivity measurements have been reported on a wide range of polymers including carbon nanofibre reinforced HOPE [52], carbon black filled LDPE-ethylene methyl acrylate composites [28], carbon black filled HDPE [53], carbon black reinforced PP [27], talc filled PP [54], copper particle modified epoxy resins [55], epoxy and epoxy-haematite nanorod composites [56], polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) blends [57], polyacrylonitrile based carbon fibre/PC composites [58], PC/MnCli composite films [59], titanocene polyester derivatives of terephthalic acid [60], lithium trifluoromethane sulfonamide doped PS-block-polyethylene oxide (PEO) copolymers [61], boron containing PVA derived ceramic organic semiconductors [62], sodium lanthanum tetrafluoride complexed with PEO [63], PC, acrylonitrile butadiene [64], blends of polyethylene dioxythiophene/ polystyrene sulfonate, PVC and PEO [65], EVA copolymer/carbon fibre conductive composites [66], carbon nanofibre modified thermotropic liquid crystalline polymers [67], PPY [68], PPY/PP/montmorillonite composites [69], carbon fibre reinforced PDMS-PPY composites [29], PANI [70], epoxy resin/PANI dodecylbenzene sulfonic acid blends [71], PANI/PA 6,6 composites [72], carbon fibre EVA composites [66], HDPE carbon fibre nanocomposites [52] and PPS [73]. 

Bryning et al. [25] have reported the preparation of carbon nanotube aerogels, reinforced with polyvinyl alcohol. These materials conduct and have structural integrity, and show promise for sensing applications. 

Electrical properties have been reported on numerous carbon fiber-reinforced polymers, including carbon nanoflber-modified thermotropic liquid crystalline polymers [53], low-density polyethylene [54], ethylene vinyl acetate [55], wire coating varnishes [56], polydimethyl siloxane polypyrrole composites [50], polyacrylonitrile [59], polycarbonate [58], polyacrylonitrile-polycarbonate composites [58], modified chrome polymers [59], lithium trifluoromethane sulfonamide-doped polystyrene-block copolymer [60], boron-containing polyvinyl alcohols [71], lanthanum tetrafluoride complexed ethylene oxide [151, 72, 73], polycarbonate-acrylonitrile diene [44], polyethylene deoxythiophe-nel, blends of polystyrene sulfonate, polyvinyl chloride and polyethylene oxide [43], poly-pyrrole [61], polypyrrole-polypropylene-montmorillonite composites [62], polydimethyl siloxane-polypyrrole composites [63], polyaniline [46], epoxy resin-polyaniline dodecyl benzene sulfonic acid blends [64], and polyaniline-polyamide 6 composites [49]. 

Han Jingquan, Lei Tingzhou, and Wu Qinglin. High-water-content mouldable polyvinyl alcohol-borax hydrogels reinforced by well-dispersed cellulose nanoparticles Dynamic rheological properties and hydrogel formation mechanism. Carbohyd Polym. 

The homogeneous dispersion of cellulose nanoparticles in a polymer matrix in order to obtain nanomaterials is due to their size, which allows penetration in hydrosoluble or at least hydrodispersible structures (as latex-form polymers) as well as dispersion of polysaccharide nanocrystals in nonaqueous media especially using surfactants and chemical grafting. Thus, one of the processing techniques of polymer nanocomposites reinforced with polysaccharide nanocrystals was carried out using hydrosoluble or hydrodispersible polymers. In this respect, the literature has reported preparation of polysaccharide particles with reinforced starch (Svagan et al. 2009), silk fibroin (Noishiki et al. 2002), poly(oxyethylene) (POE) (Samir et al. 2006), polyvinyl alcohol (PVA) (Zimmermann et al. 2005), hydroxypropyl cellulose (HPC) (Zimmermann et al. 2005), carboxymethyl cellulose (CMC) (Choi and Simonsen 2006), or soy protein isolate (SPI) (Zheng et al. 2009). 

Extrusion and impregnation, electrospinning, and multilayer films are other processes applicable for reinforced nanocomposites. Thus, preparation of cellulose whiskers reinforced with polylactic acid nanocomposites (by melt extrusion carried out by pumping the suspension of nanocrystals into the polymer melt during the extrusion process), using polyvinyl alcohol as a compatibilizer for the dispersion of cellulose whiskers within the polylactic acid matrix, was reported (de Menezes et al. 2009) bacterial cellulose whiskers incorporated into poly(oxyethylene) nanofibers by electrospinn to enhance the mechanical properties of electrospun fibers (Peresin et al. 2010) or the use of the layer-by-layer assembly technique, which maximizes the interaction between cellulose whiskers and a polar polymeric matrix (Bruno et al. 2009 Aulin et al. 2010), are some examples of nanocomposites reinforced by the last three methods. 

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