Shaped polymer fabrication

Reaction of a triol such as 1,2,6-hexanetriol with a DETOU prepolymer permits the formation of a cross-linked network. Rod-shape polymer systems (2.4 mm in diameter) were fabricated containing 30wt% levonor-gestrel and 7 wt%o micronized Mg(OH)2 as a stabilizer. These devices contained 1 wt% 9,10-dihydroxystearic acid to modify polymer erosion rate. SEM photomicrographs of the rods show evidence of surface... 

What makes plastics the most versatile of all materials is the ease with which they can be given any desired shape and form. Molding and fabrication processes, however, vary depending on the type of polymers to be processed and the end products to be made. Chapter 2, which deals with polymer fabrication processes for plastics, rubber and fiber, has been thoroughly revised in the new edition to include recent developments in the respective fields and a number of processes not covered in the previous edition. Particularly, the discussion on plastic foams and foam extrusion processes has been further broadened. 

T. Nisisako, T. Torii, Formation of biphasic Janus droplets in a micro-fabricated chaimel for the synthesis of shaped polymer microparticles, Adv. Mater. 2007, 19, 1489. 

F 754 Specification for Implantable Polytetrafluoroethylene (PTFE) Polymer Fabricated in Sheet, Tube, and Rod Shapes... 

Fig. 1.4 Schematic presentations of basic methods of shaping and fabricating ceramics. Note In the case of extrusion, homogeneous mixtures of ceramic powder and polymer are most frequently used, and extmsion is performed at a low or increased temperature under high pressure in the case of casting in moulds, a broad range of methods have been developed, from shaping of a rigid product by sucking liquid out of the deposit in the mould, to direct deposition on the mould surface of colloidal particles and of gels created in a suspension of colloidal particles (sol)...

The surface morphology of the two shape memory fabrics are shown in Fig. 10.3(a) and (b). A similar morphology was observed in both fabrics Fj and F the shape memory polymer is grafted onto individual cotton fiber or bridged within two or more cotton fibers. 

Figure 1 Typical superhydrophobic surface structure fabricated by templating method (A) replica of Co/ocas/a-like leaf surface on PDMS template (Singh et al., 2007), (B) a microporous pattern of polyvinylidene fluoride film (Li et al., 2006), (C) superhydrophobic hair shaped polymer surface grown through an AAO template (Zhang et al., 2006) and (D) water droplet resting on a polymer hot-press transferred pattern (Bormashenko et al., 2006). PDMS, polydimethylsiloxane AAO, aluminum oxide. Images reprinted with permission from (A, B) Elsevier, Copyright2007and2006 respectively, (C, D) American Chemical Society, Copyright2006.

Silicones, a category of polymers, are widely used in sealants, adhesives, medical applications, and insulation, and can often be made in soff formats with flexibility, foldability, and stretch-ability. On the contrary, electronics represent a totally different field, where devices are usually rigid, and retain static shapes once fabricated. The overlapping between these two soft and stiff worlds has not yet been seen until a few years ago. 

From the point of view of technology, it is convenient to classify polymers as thermosetting and thermoplastic. The former set by chemical crosslinks introduced during fabrication and hence do not change appreciably in their deformability with changes in temperature. Thermoplastics, on the other hand, soften and/or melt on heating and can therefore be altered in shape by heating... 

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