Poly solution-grown

Figure 16 (a) Morphology of solution-grown poly(lactide) stereocomplexes and (b) the... 

In general, it is possible to visualize individual solution-grown lamellae by both CM-AFM and TM-AFM. The same is true for many melt-grown lamellae. Due to the contrast based on the difference in energy dissipation between amorphous and crystalline phases in the TM-AFM phase images, the lamellae can be seen with excellent contrast, and hence, high resolution. Two examples of lamellae of poly (ethylene oxide) (PEO) viewed in flat-on and edge-on projection are shown in Fig. 3.19. 

Fu, B., Hsiao, B., Chen, G., Zhou J., Koyfman, I., Jamiolkowski D. D. and Dormier E., Structure and property studies of bioabsorbable poly(glycolide-co-lactide) fiber during processing and in vitro degradation. Polymer, 43,5527,2002. Fischer, E. W., Sterzel, H. J. and Wegner, G., Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical reactions, Kolloid-Z. Z. Polym., 251,980. 1973. 

Poly(vinylidene fluoride) (hereafter,the acronym PVDF will be used) has been considered to have three crystal modifications depending on the crystallization condition such as the species of precipitation solvent,the concentrations of polymer and the annealing temperature in crystallization (1 5). These suggest that the conformations in solution-grown crystals are closely related to those in solution used for the growth of the crystal. 

Fig. 24. DTA melting peak temperature as a function dt heating rate for poly-ethylenes of different crystal morphologies. Curve 1, attended diain crystak curve 2, slowly cooled melt crystallized spherulites curve 3, fast cooled mdt crystallized spherulites curve 4, solution grown folded chain single crystals.

Solution-grown single lamellar crystals of, eg, PEO (147), POM (148), PE (149,150), syndiotactic PP, poly(dimethyl silane) (151), poly(4-methyl-pentene) (152), and poly[(i )-3-hydroxybutyrate] (153) deposited onto solid substrates have been studied by SFM. The habit and thickness of the lamellae in flat-on projection are directly accessible and in addition to these data, which have previously been typically provided by TEM in conjunction with shadow evaporation techniques (4), more subtle details of domain boundaries and fold direction orientation have been revealed. In Figure 14, the habit of a collapsed PE lamellae is depicted, as well as the anisotropic lateral force recorded in the different fold sectors (154). 

Polymer Lamellar Crystals Grown from Solution. Similarly to the regular array of polymer chains exposed at extended-chain fibrillar crystals, the folded sections of polymer molecules at the fold plane of solution-grown single crystals can cause anisotropy of friction (Figures 6). This has been observed for a variety of materials, such as POM, PE, and poly(4-methyl-l-pentene) (11 -13). The explanation proposed for this observation is based on the presence of oriented folds at the surface of the fold plane. 

Polylactides, 18 Poly lactones, 18, 43 Poly(L-lactic acid) (PLLA), 22, 41, 42 preparation of, 99-100 Polymer age, 1 Polymer architecture, 6-9 Polymer chains, nonmesogenic units in, 52 Polymer Chemistry (Stevens), 5 Polymeric chiral catalysts, 473-474 Polymeric materials, history of, 1-2 Polymeric MDI (PMDI), 201, 210, 238 Polymerizations. See also Copolymerization Depolymerization Polyesterification Polymers Prepolymerization Repolymerization Ring-opening polymerization Solid-state polymerization Solution polymerization Solvent-free polymerization Step-grown polymerization processes Vapor-phase deposition polymerization acid chloride, 155-157 ADMET, 4, 10, 431-461 anionic, 149, 174, 177-178 batch, 167 bulk, 166, 331 chain-growth, 4 continuous, 167, 548 coupling, 467 Friedel-Crafts, 332-334 Hoechst, 548 hydrolytic, 150-153 influence of water content on, 151-152, 154... 

X-ray diffraction techniques can be used to establish the structure of crystalline polymers. Measurements are typically made on crystalline lamellar platelets grown from dilute solution, fibres or stretched films. Such methods have been applied to several different inorganic polymers. For example, based on measurements on stretched samples of silicone rubber, poly(dimethylsiloxane) (Me2SiO) has been shown to possess a helical conformation (Figure 8.4). ... 

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