Copolyethers characterization

Description of termotropic liguid-ciystalline copolyether polyethyleneterephtalat and terephtaloyl-di(n-oxybenzoat) is given in this work [2], Microstructure of given block-copolymer is characterized by means of IR-spectroscopy with fourie-transformation. Pictures of polarization microscopy show, that copolyether is nematic liguid-crystalline polymer. 

It should be noted that SC copolymers based on nonmesogenic SCs and NLO mes-ogenic SCs offer the opportunity to fine-tune the polymer properties by varying the ratio of the NLO mesogenic SCs, although care must be taken to characterize the product, since the final ratios of the SCs may not correspond to the feed concentrations. An interesting example is the series of copolyethers prepared by chemical modification of atactic polyepichlorohydrin with the sodium salt of 4-cyano-4 hydroxybiphenyl [188, 207] (45). 

Scamporrino, E. and Ttalini, D., Main Chain Porphyrin Polymers. 2. Synthesis and Characterization of Some Copolyethers and Their Metal Derivatives, Macromolecules, 25, 6605, 1992. 

The goal of this paper is to review our present information on the synthesis and characterization of LC polyethers and copolyethers based on 4,4 -dihydroxy-a-methylstilbene (HMS) and 4,4 -dihydroxybiphenyl (HB) with a, (i)-dibromoalkanes. 

Table 2. Synthesis and Characterization of Polyethers and Copolyethers Based on 4,4 -Dihydroxy-a-methylstilbene, 1,5-Dibromopropane, and 1,7-Dibromoheptane... 

The experimental data concerning the synthesis and characterization of the copolyethers based on HB, 1,7-dibromoheptane and 1,9-dlbromononane are summarized in Table 5. In contrast to the copolyethers of HMS, which are all amorphous the copolyethers of HB are crystalline and present anisotropic melts exhibiting smectic textures. Examples of heating and cooling DSC scans for the copolymer PHB-7,9-20 are presented in Figure 9. 

Tsai, R.S. and Y.D. Lee, S)mthesis and characterization of block copolyether-esters with poly(tetramethylene 2,6-naphthalenedicarboxylate) segments. journal of Applied Polymer Science, 66(7) p. 1411.1997. 

Boulares A, RozSs L, Tessier M and MarSchal E (1998) Synthesis and characterization of poly(copolyethers-6-polyamides). I. Structural study of polyether precursors, J Macromol Sci - Pure Appl Chem A35 933-953. 

The values obtained by elemental analysis and spectroscopy are common to the block copolymer and to a mixture of the corresponding homopolymers. In some very rare cases, it is possible to characterize the junction between the blocks. Boulares [4,5] prepared polyamide-6-copolyethers by poly condensation of an a,to-dicarboxylic-oligoamide (PA, = 1200) with different a,w-dihydroxy-copolyethers (PE, = 1000) their NMR spectra clearly show the signals (in ppm) relative to the ester junction between the blocks (Scheme 37), even though the molecular mass of the block copolymer is close to 20000. SEC often gives an unambigous proof of the copolymer formation. 

Boulares A, Tessier M and Mar chal E (2000) Synthesis and characterization of poly(copolyethers-6Zocfc-polyamides) II. Characterization and properties of the multiblock copolymers, Polr/mer 41 3561-3580. 

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