Synthesis by direct polycondensation

UEDA OKADA Ordered Polymer Synthesis by Direct Polycondensation 445... 

Kishimoto T, Morihara Y, Osanai M, Ogata S-1, Kamitakahara M, Ohtsuki C, Tanihara M. Synthesis of poly(Pro-Hyp-Gly)n by direct polycondensation of (Pro-Hyp-Gly)n, where n = 1, 5, and 10, and stability of the triple-helical structure. Biopolymers 2005 79 163-172. 

When the ratio of template to acid is close to 0.5, the viscosity of the product is more than 3 times higher than the viscosity of the polymer obtained without the template. PEO participates in the change of local concentration by interaction with carbonyl groups, but not in the activation. Solution of LiCl in N-methylpyrrolidone with PlOCeHsls was found very effective system for synthesis of amides by the direct reaction of acids with amines in the presence of polymeric matrix. High molecular weight poly(aminoacids) obtained by direct polycondensation reaction, promoted by triphenyl phosphite and LiCl in the presence of poly(vinylpyrrolidone), were synthesized by Higashi et al The results for polymerization of L-leucine in the presence of poly(vinyl pyrrolidone) are presented in the Table 6.3. 

Yamaoka, X, Takahashi, Y., Ohta, T. et al. (1999) Synthesis and properties of multiblock copolymers consisting of poly(L-lactic acid) and poly(oxypropylene-co-oxyethylene) prepared by direct polycondensation. Journal of Polymer Science Part A Polymer Chemistry, 37, 1513-1522. 

Kim KW, Woo SI (2002) Synthesis of high-molecular-weight poly(L-lactic acid) by direct polycondensation. Macromol Chem Phys 203(15) 2245-2250... 

Thionyl chloride has been reported as an activator in the synthesis of polyamides by direct polycondensation. ... 

Achmad, F., Yamane, K., Quan, S., Kokugan, K., 2009. Synthesis of polylactic acid by direct polycondensation under vacuum without catalysts, solvents and initiators. Chem. Eng. J. 151, 342—350. 

Jikei et al. have described the synthesis of aromatic HBPA copolymers by direct polycondensation of 3-(4-aminophenoxy)benzoic acid (AB monomer) and 3,5-bis(4-aminophenoxy)benzoic acid (AB monomer) in the presence of TPP and pyridine as condensation agents [69]. The structure of resulting polymers was confirmed... 

The synthesis of high-molecular-weight PLA is generally carried out by the ring-opening polymerization of lactide or by direct polycondensation of lactic acid. Tin-based catalysts are typically used in both cases, either alone or in combination with p-toluenesulfonic acid. ° ... 

Ogata, N., Sanui, K., Tan, S., Synthesis of Ahfatic Polyamides by Direct Polycondensation with Triphenylphosphine, Polymer, J. 1984, 16, 569. 

Imai Y, Kajiyama M, Ogata S and Kakimoto M (1985) Improved synthesis of poly-ether-aramid multi-block copolymers by direct polycondensation. Polymer J 17 1173-1178. 

Our group has initiated a synthesis of ordered polymer from nonsymmetric monomers by direct polycondensation. In the previous papers, we reported a successful synthesis of ordered polyamides (head-to-head or tail-to-tail) from a synunetric monomer and a nonsynunetric monomer, (7,2), and ordered polyamides (head-to-tail) from a synunetric monomer and a nonsynunetric monomer or a pair of two synunetric monomers (3). 

On the basis of the above findings, we initiated the synthesis of ordered (-abedef-) polymer from three nonsymmetric monomers, XabX, YcdY and ZefZ by direct polycondensation. 

A powerful and efficient method for the preparation of poly(ketone)s is the direct polycondensation of dicarboxylic acids with aromatic compounds or of aromatic carboxylic acids using phosphorus pentoxide/methanesulfonic acid (PPMA)16 or polyphosphoric acid (PPA)17 as the condensing agent and solvent. By applying both of these reagents to the synthesis of hexafluoroisopropylidene-unit-containing aromatic poly(ketone)s, various types of poly(ketone)s such as poly(ether ketone) (11), poly(ketone) (12), poly(sulfide ketone) (13), and poly-... 

This review summarizes different synthetic methods of obtaining either molecular or maeromolecular fluorinated telechelic compounds. These compounds may be obtained either by direct synthesis or by syntheses which need many steps. Thus, reactions of polycondensation, polymerization, telomerization, fluorination of oligomers or the use of functional initiators are described in detail. On the other hand, the emphasis is also focussed on the interest of each method of preparation. Specific properties (solubility, thermal stability, surface properties. ..) of the obtained fluorinated telechelic products are discussed with regard to modern industrial requirements. We can observe that the compounds obtained by recently developed methods may be listed in two classes those which exhibit better surface properties and those which have better thermal stability. 

Such approach of the synthesis by solid-state reaction is especially attractive with precursors that present silanol functions. Here again, the supramo-lecular association promoted by these functions combined with their reactivity allows to directly transform by a simple thermal treatment a molecular precursor to a polymeric hybrid material. Liu, et al. have reported on the possibility to polycondense silanols in the solid state [95], and Corriu et al. have obtained the formation of layered materials by condensation of bis-trisilanol precursors [96,97],... 

Scheme 13. Folybenzimidazole synthesis, exemplified by the direct polycondensation of 3,3, 4,4 -tetraaminodiphenyl ether with isophthalaldehyde in solution...

Molecular composites in terms of synthesis The reinforcements are also formed by the in-situ reaction in the matrix polymers. Such methods are another way to pursue the limit of molecular dispersion of reinforcing materials. One example is found in the in-situ precipitation of reinforcing silica in polydimethyl siloxane networks with the sol-gel methods [21], Another example is the direct polycondensation of p-aminobenzoic acid or p-hydroxybenzoic acid from their monomers in solutions of polyarylate [22]. Mechanical properties of the cast films indicated increase in modulus and tensile strength at elevated temperatures. 

Sulfonated ACPs are prepared both by direct sulfonation and by polycondensation and polycyclocondensation of sulfonated compounds. Synthesis of the first sulfonated poly(p-phenylene) was reported by Wegner and co-workers [103]. The Suzuki coupling of diboronic ethers with dibromo-aromatic monomers furnished poly(p-phenylene) with 95% yield. 

The grafting is performed by direct reaction of 10 on the solid obtained after elimination of the template. The direct synthesis is a procedure which implies the presenee of 10 as a reagent during the preparation of the SiOa matrix. In this case 10 has a spacer with lipophilic properties, compatible with the core of the micelle. The C-SiOi.5 bond is attached to the matrix during the hydrolytic polycondensation, which permits the formation of Si02. 

Several synthetic strategies have been developed to prepare phosphonated aromatic polymers, where the acid groups are attached either directly " or via spacers to an aromatic backbone. " These polymers can be prepared either by post-phosphonation of prepolymers via, e.g. transition metal catalyzed Michaelis-Arbuzov reactions and lithiation chemistiy, or by direct polymerization of phosphonated monomers via polycondensation. Both synthetic strategies then require hydrolysis of the esters to obtain the free acid. The former strategy requires the formation of C-P bonds in the polymer structure, and the latter necessitates the synthesis and purification of suitable monomers. 

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