The term sugar diols is used throughout this review as a nickname for diols that are usually derived from saccharides. Typical examples of such “sugar diols” are the bicyclic ethers L-sorbitol (A), L-iditol (z), and L-mannitol (3),—where 1 and 1 are commercial monomers. Furthermore, the acetals 4, 5, 6, and 7 should be mentioned, which are all commercial. These sugar diols have recently attracted increasing interest as monomers for the synthesis of various polycondensates. Several reasons are responsible for this tendency. 1. All sugar diols can be prepared from saccharides (although other synthetic routes may also be available) and thus are monomers based on renewable resources. 2. Most sugar diols (e.g., 1–4 and 7) are nontoxic and their polyesters derived from aliphatic dicarboxylic acids are sensitive to hydrolysis. Such aliphatic polyesters will degrade in the course of several months in contact with warm neutral water and thus are considered to be useful biodegradable materials. 3. All suga...

“Sugar Diols” as Building Blocks of Polycondensates

(S)-((2-Methylbutyl)thio)hydroquinone was prepared from benzoquinone and (S)-2-methylbutyl mercaptan. One series of cholesteric copolycarbonates was prepared from this chiral hydroquinone, methylhydroquinone, and 4,4‘-dihydroxybiphenyl by interfacial polycondensation with diphosgene. All copolycarbonates were noncrystalline and decomposed upon heating above 250 °C. A Grandjean texture was only observed for one sample. A second series of cholesteric copolycarbonates was prepared from isosorbide, methylhydroquinone, and 4,4‘-dihydroxybiphenyl. Four different polycondensation methods were studied and compared in this case. The best results were obtained by polycondensation in pyridine containing organic cosolvents. Two copolycarbonates of isosorbide were obtained which formed a broad cholesteric phase with a Grandjean texture.

Polymers of Carbonic Acid. 22. Cholesteric Polycarbonates Derived from (S)-((2-Methylbutyl)thio)hydroquinone or Isosorbide

This work presents a new synthetic approach to aromatic and aliphatic polycarbonates by melt polycondensation of bisphenol A diacetates with alkylene- and arylenediphenyl dicarbonates. The diphenyl dicarbonates were prepared from phenyl chloroformate and the corresponding dihydroxy compounds. The process involved a precondensation step under a slow stream of dry argon with the elimination of phenyl acetate, followed by melt polycondensation at high temperature and under vacuum. The potential of this reaction is demonstrated by the successful synthesis of a series of aromatic-aromatic and aromatic-aliphatic polycarbonates having inherent viscosities from 0.19 to 0.43 dL/g. Thus low to intermediate molecular mass polymers were obtained. The (13)C-NMR spectra of the carbon of the carbonate group showed that the formed polycarbonates contain partial random sequence distribution of monomer residues in their chains. The polycarbonates were characterized by inherent viscosity, FTIR, (1)H-NMR and (13)C-NMR spectroscopy. The glass transition temperatures, measured by DSC, of the polycarbonates were in the range 13-108 degrees C. The thermogravimetric curves of showed that these polymers have good thermal stability up to 250 degrees C. The present approach may open the door for novel polycarbonates containing other organic functional groups.

https://www.mdpi.com/1420-3049/15/5/3661/pdf

Synthesis and Characterization of Polycarbonates by Melt Phase Interchange Reactions of Alkylene and Arylene Diacetates with Alkylene and Arylene Diphenyl Dicarbonates

Three series of thermotropic liquid crystalline polycarbonates and poly(ester-carbonate)s were prepared by solution polycondensation of 4,4′-biphenyldiol (BP), 4′-hydroxybiphenyl-4-hydroxybenzoate (HHB), or 4-hydroxyphenyl-4″-hydroxybiphenyl-4′-carboxylate (HHBP), as mesogenic unit, with 1,10-bis(p-hydroxybiphenoxy)decane (N10), bisphenol A (BPA), 4,4′-dihydroxy-diphenyl ether (BPO), 4,4′-[phenylbis(oxy)]bisphenol (BPOO), methylhydroquinone (MeHQ), or phenylhydroquinone (PhHQ). One series of cholesteric poly(ester-carbonate)s were also prepared by using HHBP, the aromatic diols mentioned above and isosorbide as the chiral moiety. All polycondensations were implemented in pyridine by using triphosgene as the condensation agent. The synthesized polycarbonates were characterized by viscometer, FTIR, DSC, TGA measurements, polarizing microscopy equipped with a heating stage, and WAXD powder pattern. In this study, it was found that the liquid crystalline properties of polycarbonates strongly rely on the mesogenic unit applied. HHBP-series exhibits a wide temperature region of liquid crystalline (LC) phase even with 50% of bisphenol A (BPA), which is a V-shaped structure and usually destroys liquid crystalline properties. In addition, homopolycarbonate with HHBP structure possesses extraordinarily low phase-transition temperature and wide liquid crystalline phase range, due to its asymmetric structure. This asymmetric structure results in head-to-tail, head-to-head, and tail-to-tail random conformation of polymer chain. The isosorbide containing poly(ester-carbonate)s formed cholesteric phase, which showed homogeneous blue, green, or red Grandjean texture upon shearing in molten state and the Grandjean texture could be frozen easily while quenching the sample to the room temperature. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1852–1860, 2000

Studies on the synthesis and properties of thermotropic liquid crystalline polycarbonates. VII. Liquid crystalline polycarbonates and poly(ester‐carbonate)s derived from various mesogenic groups

Copolymers [COPh(CO) 2 N-PhCOOPh(Ph)O] m [P(O)(R)OPh(Ph)] n (R = Ph, OPh, Me) were prepared by copolycondensation of trimellitic dichloride with phosphate- or phosphonate dichloride and with silylated phenylhydroquinone. The copolymers are amorphous and stable up to 410-425°C in air.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/pola.1992.080300220

LC‐polyimides. VII. Thermotropic poly(ester‐imide)s derived from trimellitic acid with phosphonate or phosphate groups in the main chain

Preparation des polymeres [OPhPhOCO-(OPh(X)OCO) m ] n (X-H,Cl,Me,Ph,m=1,2,3,4), [OPhPhOCO-/(OPhZPhOCO] n (Z=O,CO,S,SO 2 ,C(Me) 2 ) [OPhPhOCO/OPhXPhOCO/OPh(Me)OCO] n (x=O,CO,S) [OPhPhOCO/OPhC(Mc) 2 PhOCO/(OPhOCO) m ] n (m=1,2,3) par polycondensation interfaciale. Tous sont amorphes avec des Tg variant entre 90 et 170°C. Certains presentent des phases nematiques

Polymers of carbonic acid. 3. Thermotropic polycarbonates derived from 4,4'-dihydroxybiphenyl and various diphenols

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Polymers of carbonic acid. 3. Thermotropic polycarbonates derived from 4,4'-dihydroxybiphenyl and various diphenols