Poly crystallization behavior

An example of the incorporation of an external component on the crystallization behavior of triblock copolymers was given by Schmalz et al. [126]. They obtained PS-fo-poly(ethylene-co-propylene)-fo-PE (PS-fo-PEP-fr-PE) triblock copolymers from the hydrogenation of PS-fr-PI-fo-PB. PS-fo-PEP-fr-PE triblock copolymers have the peculiarity that PEP and PE have an interaction parameter of 0.007 at 120 °C therefore, they form a homogeneous melt, which is segregated from the PS block and can be considered as an intermediate case between diblock and triblock copolymers. The crystallization of the PE block occurs at about 60 °C and the authors evaluated the influence of the incorporation of a solvent during the crystallization and segregation processes under... 

Lipases not only catalyze ROP but also catalyze transacylation reactions. This was exploited by preparing random copolymers of TMC with CL or PDL [91, 92, 159]. The PDL-TMC poly (carbonate-esters) show co-crystallization behavior of... 

Crystallization behavior in miscible blends containing crystallizable components has been extensively studied [174-180]. Generally, when a crystallizable component is mixed with an amorphous component its melting temperature goes down and its crystallinity lowers. The same trend has been reported for blends with intercomponent hydrogen bonding such as PCL/STVPh [181], PCL/poly(hydroxyl ether of bisphenol A) [182] and phenoxy resin/PEO [183]. 

K.-S. Kim, I.-J. Chin, J.S. Yoon, H.J. Choi, D.C. Lee, and K.H. Lee, Crystallization behavior and mechanical properties of poly(ethylene oxide)/poly(l-lactide)/poly(vinyl acetate) blends, J. Appl. Polym. Sci., 82(14) 3618-3626, December 2001. 

Finter, J. and Wegner, G. The relation between phase transition and crystallization behavior of l,4-trans-poly(butadiene). Makromol. Chemie 182, 1859 (1981) (see here and Ref. 3 for older data)... 

After having studied in our laboratory, polymer blends of amorphous polymers poly-c-caprolactone and poly (vinyl chloride) (1,2) (PCL/ PVC), blends with a crystalline component PCL/PVC (3,4), poly(2,6-dimethyl phenylene oxide) (PPO) with isotactic polystyrene (i-PS) (5) and atactic polystyrene (a-PS) with i-PS (6), we have now become involved in the study of a blend in which both polymers crystallize. The system chosen is the poly(1,4-butylene terephthalate)/poly(ethylene terephthalate) (PBT/PET) blend. The crystallization behavior of PBT has been studied extensively in our laboratory (7,8) this polymer has a... 

Having synthesized a number of complexes of monoalkoxystilbazoles, we explored the effect of using various poly(alkoxy)stilbazoles, given the interesting mesomorphism found in polycatenar mesogens (Section VI,A,3). This work is discussed in detail elsewhere 24). Here, we give an overview of the work to enable the reader to see the overall pattern of liquid-crystal behavior and the issues that arise. 

To investigate the crystallization phenomena induced by the external field, a cyclic force is imposed on a small portion of molecules in the amorphous structure, in addition to tiie inherent intermolecular forces. As a practical matter, this force may be applied to susceptor molecules (molecules witii dangling or floating bonds, or other defects) tiirough direct electric fields, electric fields induced by the external magnetic field, or other excitation sources. In tiiis study, it is assumed that some molecules can act as susceptors of the external field, for tiie sole purpose of inducing artificial molecular movements selectively and of observing tiie subsequent crystallization behavior. As discussed previously, the results of this study could provide a clue to mechanisms involved in the athermal crystallization of a-Si to poly-Si, which is induced by the field-enhanced molecular movements. 

Blend films of poly(L-lactide) (PLLA) and poly(vinyl alcohol) (PVA) were synthesized. The component interaction, crystallization behavior, and miscibility of these blends were studied by solid-state NMR. ... 

While techniques presently employed for quantitative description of microstructure all provide some sort of numerical representation, none are completely adequate for insertion into continuum theories that describe material behavior at the next higher length and time scales. Some success has been achieved in this regard by employing the ODF with single crystal elastic constants to obtain the bulk elastic constants [12], or upper and lower bounds thereto [13], for a textured poly crystal. 

Poly(ethylene terephthalate) Poly(ethylene terephthalate) is a widely used semicrystalline polymer. The macroscopic properties of PET such as thermal, mechanical, optical, and permeation properties depend on its specific internal morphologies and microstructure arrangement. It can be quenched into the completely amorphous state, whereas thermal and thermomechanical treatments lead to partially crystallized samples with easily controlled degrees of crystallinity. The crystallization behavior of thermoplastic polymers is strongly affected by processing conditions [91-93]. 

Accordingly, the influence of MW on the crystallization behaviors of semicrystalline polymers has been studied in various articles. For example, linear crystal growth rates of poly(ethylene oxide) and poly(ethylene succinate) (PES) reach a minimum value at a critical MW. This value is related to the crystallization transition from an extended chain to a folded chain conformation [96,97], suggesting that high MW polymers require sufficient reconformation time to achieve an ordered structure. As evidence of this MW dependence of the semicrystalline polymer on... 

It was shown already above that cis-1,4-poly butadiene melts in one step with the expected entropy of fusion. In contrast, cis-l,4-poly(2-methylbutadiene) (natural rubber) has a more complicated fusion and crystallization behavior . The reported entropy of fusion of the common monoclinic (P2ja) crystal polymorph is only 14.4 J/(K mol), less than half of the expected value. The crystal structure has been reported statistically disordered, but only relative to packing of chains that are mirror images of each other along the crystallographic a-axis. Such geometric disorder cannot account for a 50% decrease in entropy of fusion. A full study of the thermod5mamic functions as available for the polybutadienes would be of value. 

Metal-containing poly-yne polymers with molecular weight (Mw) of ca 1.2 xlO were soluble in usual organic solvents such as benzene, methylene chloride, tetrahydrofuran etc. The thermal stability of the polymers was increased with the metals, in the order of Pt > Pd >Ni. Films with a thickness of several microns and with a tensile strength as large as 9.0 X 10 g/mm were fabricated from the Pt-containing polymer. One of the characteristics of these polymers is their lyotropic liquid crystal behavior in solution. Some representative polymers prepared are listed in Table 15. 

Poly( 1,4-cyclohexylenedimethylene terephthalate-c< -1,4-cyclohexyl-enedimethylene 2,6-naphthalate) (P(CT-c< -CN)) copolymers behave similarly with respect to crystallization behavior than poly(ethylene-co-butyl-ene 2,6-naphthalate) copolymers. Poly(ethylene 2,6-naphthalate-co-l,4-cyclohexylenedimethylene 2,6-naphthalate) (P(EN-co-CN)) copolymers do not crystallize in the middle of copolymer composition, whereas poly-(hutylene 2,6-naphthalate-c< -1,4-cyclohexylenedimethylene 2,6-naphthalate) (P(BN-co-CN)) and poly(hexamethylene 2,6-naphthalate-co-l,4-cy-clohexylenedimethylene 2,6-naphthalate) (P(HN-c< -CN)) copolymers exhibit clear melting and crystallization peaks. This behavior indicates that both P(BN-co-CN) and P(HN-co-CN) copolymers exhibit a co-crystallization behavior. P(BN-co-CN) copolymers exhibit a eutectic melting and isodimorphic co-crystallization. 

Shin EJ, Jeong W, Brown HA, Koo BJ, Hedrick JL, Waymouth RM (2011) Crystallization of cyclic polymers synthesis and crystallization behavior of high molecular weight cyclic poly (epsilon-caprolactone)s. Macromolecules 44 2773-2779... 

Avella, M., Martuscelli, E. Poly-d(-)(3-hydroxybutyrate)/poly(ethylene oxide) blends phase diagram, thermal and crystallization behavior. Polymer 29(10), 1731-1737 (1988)... 

Miyata, T. and Masuko, T. (1998) Crystallization behavior of poly(L-lactide). Polymer, 39, 5515-5521. 

Di Lorenzo, M.L. (2005) Crystallization behavior of poly(L-lactic acid). European Polymer Journal 41, 569-575. 

Tsuji, H., Takai, H., Fukuda, N. and Taldkawa, H. (2006) Non-isothermal crystallization behavior of poly(L-lactic acid) in the presence of various additives. Macromolecular Materials and Engineering, 291,325-335. 

Pan, R, Zhu, B., Dong, T. and Inoue, Y. (2008) Poly(L-lactide)/layered double hydroxides nanocomposites Preparation and crystallization behavior. Journal of Polymer Science Part B Polymer Physics, 46, 2222-2233. 

Pan, P, Zhu, B., Kai, W. et al. (2007) Crystallization behavior and mechanical properties of bio-based green composites based on poly(L-lactide) and kenaf fiber. Journal of Applied Polymer Science, 105, 1511-1520. 

Shibata, M., Inoue, Y. and Miyoshi, M. (2006) Mechtmical properties, morphology, and crystallization behavior of blends of poly(l-lactide) with poly(butylene succinate-co-l-lactate) and poly(butylene... 

Sun L, Liu YX, Zhu L, Hsiao BS, AvUa-Orta CA (2004) Self-assembly and crystallization behavior of a double-crystalline polyethylene-block-poly(ethylene oxide) diblock copolymer. Polymer 45 8181-8193... 

Jikihara Y, Saito T, Yamane H (2006) Effect of thermal history on the crystallization behavior of bacterial poly(3-hydroxybutyrate-co-hydroxyhexanoate) and the cold drawability of melt spun fibers. Sen i Gakkaishi 62 115-122... 

Jeong YG, Jo WH, Lxe SC. Synthesis and crystallization behavior of poly(m-methylene 2,6-naphthalate-co-1,4-cyclohexylenedimethylene... 

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