Poly whisker

Crystal structure analysis for poly(p-benzoic acid) whisker [40] and stmctural study of stacking faults in s5mdiotactic pol5 ropylene [41] were carried out. 

Fig. 7 Logarithmic plot of the shear modulus G (Pa) for a composite specimen of poly(styrene-co-butyl acrylate) reinforced by 6 wt % cellulose whiskers, as a function of temperature. This specimen is compared with a control sample that does not contain any whisker. (Reproduced from [77])...

Many monomers can be grafted by redox polymerization to the magnetic core [magnetic material embedded in poly(vinyl alcohol) matrix nominally 100% cross-linked with glutaraldehyde] to get whisker-type resins " . Acrylic acid and acryl-... 

Pyrolysis of a perylene-tetracarboxylic dianhydride monomer above 520 C resulted in vapor-phase condensation of poly-peri-naphthalene (PPN), a representative one-dimensional graphite polymer. PPN was obtained as fine whiskers with rectangular cross sections and exhibited electrical conduction behaviors characteristic of low-dimensional disordered systems. At HTT s above 2800 C,... 

Figure 6.8. Effect of temperature on the grafting of poly(THF) onto carbon whisker. [Adapted, by permission tfom, Tsubokawa N, Yoshihara T, Coll. Surfaces, 81, 1993, 195-201.]...

The free radical polymerization of styrene initialized by iniferter is influenced by chemical binding of iniferter on the surface of the silica." This reaction is used for grafting the polymer onto the surface of the silica. A similar approach is used when carbon whisker is incorporated during the graft-polymerization of methyl methacrylate. Depending on how the whisker is prepared, surface conversion can be increased up to twelve times compared to a polymerization with no whisker present. The addition of graphite to the poly esterification reaction doubles the molecular weight of the polymer. ... 

Dm KJ, Moulton J, Smith P (1993) Whiskers of poly(3-alkylthiophene)s. J Polym Sci B Polym Phys 31 735... 

Reinforced Structural Resins. Polyesters and polyepoxides are reinforced with E- or S-glass strands, mats, or cloth raising their tensile strength 10-20 times and their modulus of elasticity 10-100 times, approaching the properties of steel. Reinforced with graphite, boron, or the new poly-p-benzamide fiber or whiskers, novel composites surpass steel. 

For microscopy, a film of poly(pyrrole) was coated onto a sample of YBa2Cu 02 that was partially masked with a strip of insulating Apeizon wax which was then removed with methylene chloride. In another experiment, a miniature whisker of poly(pyrrole) was grown onto a ca. 40pm diameter YBa.Cu.Oy electrode prepared as described previously (15). A 300 overiayer of gold was deposited onto the whisker structure before the SEM work. 

Figure 4. (B) Scanning electron micrograph of a poly (pyrrole) whisker grown underneath a YBajCiuo microelectrode. Approximate dimensions and location of the underlying electrode are Indicated in the upper central portion of the figure. The interface between the epoxy and the poly (pyrrole) is delineated by a broken line. S = 40 pm.

Nanofibers based on poly(vinyl alcohol) as the matrix, and nanocrystals of a-chitin (ca. 31 nm in width and ca. 549 nm in length) as the nanofiller were prepared by Junkasem et al. [51]. The average diameters of the electrospun fibers ranged between 175 and 218 nm. The addition of increasing amounts of the whiskers caused the crystallinity of poly(vinyl alcohol) within the nanocomposite materials to decrease and the glass transition temperature to increase. 

Finally, signiflcant contrast increase of stained samples was reported when the HAADF-STEM technique was used for several systems, such as cellulose microfibers and whiskers within poly(lactic acid) [85],... 

L. Petersson, I. Kvien, and K. Oksman, Stmcture and thermal properties of poly (lactic acid)/cellulose whiskers nanocomposites materials. Compos. Sci. Technol, 67 (2007)2535-2544. 

Morin, A., Dufresne, A., Nanocomposites of chitin whiskers from riftia tubes and poly(caprolactone). Macromolecules. 6, 2190-2199 (2002), DOI 10.1021/ma011493a. 

Petersson, L., Kvien, I., Oksman, K., Structure and thermal properties of poly(lactic acid)/cellulose whiskers nanocomposite materials. Composites Science and Technology. 11-12, 2535-2544 (2007), DOI http //dx.doi.0rg/lO.lOl6/j.compscitech.2006.12.012. 

The cellulose based materials that are used as nano-reinforcements are cellulose nanocrystals (i.e. whiskers and nanospheres), nanofibrillated cellulose, regenerated cellulose nanoparticles and electrospun nanofibers. A wide range of polymer matrices have been used to form cellulose nanocomposites. Synthetic polymers such as polypropylene, poly(vinyl chloride) (PVC) [102], waterborne epoxy [103], waterborne polyurethane [104], polyurethane [105], poly-(styrene-co-butyl acrylate) [106], poly(oxyethylene) [107], polysiloxanes [108], polysulfonates [109], cellulose acetate butyrate [110,111], poly(caprolactone) [112], poly(viny 1 alcohol) [113] and poly (vinyl acetate) [114]. Different biopolymers such as starch-based... 

A twin extruder is used to compound a thermoplastic polymer with a whisker suspension. Such suspension is added in an extruder zone where the PLA is melted by means of a peristaltic pump. The extmder has a venting system that is used to remove the liquid phase of the whisker suspension. Kamel [81] has compounded PLA-malic anhydride and poly (ethylene glycol) with cellulose whiskers... 

Electrospinning processes are used to prepare nanocomposite fiber mats. In order to prepare nanocomposite fiber mats, mixtures containing the polymer solution and cellulose whiskers solution are placed in the appropriated electrospinning setup. Peresin et al. [128] have produced nanocomposite mats of poly (vinyl alcohol) (PVA) reinforced with cellulose nanocrystals using this electrospinning technique. Smooth nonwoven mats with homogeneous nanofibers were obtained. Park et al. [129] have also incorporated cellulose whiskers into nanofibers of polyethylene oxide (PEO) by the electrospiiming process. 

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