Ring-opening polymerization sugars

Enzyme activity for the polymerization of lactones was improved by the immobilization on Celite [93]. Immobilized lipase PF adsorbed on a Celite showed much higher catalytic activity than that before the immobilization. The catalytic activity was further enhanced by the addition of a sugar or poly(ethylene glycol) in the immobilization. Surfactant-coated lipase efficiently polymerized the ring-opening polymerization of lactones in organic solvents [94]. 

The biodegradable polymer available in the market today in largest amounts is PEA. PEA is a melt-processible thermoplastic polymer based completely on renewable resources. The manufacture of PEA includes one fermentation step followed by several chemical transformations. The typical annually renewable raw material source is com starch, which is broken down to unrefined dextrose. This sugar is then subjected to a fermentative transformation to lactic acid (LA). Direct polycondensation of LA is possible, but usually LA is first chemically converted to lactide, a cyclic dimer of LA, via a PLA prepolymer. Finally, after purification, lactide is subjected to a ring-opening polymerization to yield PLA [13-17]. 

Sumitomo, H. and M. Okada, Sugar Anhydrides and Related Bicyclic Acetals, Chap. 5 in Ring-Opening Polymerization, Vol. 1, K. J. Ivin and T. Saegusa, eds., Elsevier, London, 1984. 

M. Okada, Y. Yamakawa, and H. Sumitomo, Chemical synthesis of (1 3)-/i-D-glucopyranan by ring-opening polymerization of a 1,3-anhydro sugar derivative, Macromolecules, 24 (1991) 6797-6799. 

M. Ogawa, K. Hatanaka, and T. Uryu, Synthesis of a novel cellulose-type hexopyranan 6-deoxy-(l - 4)-u-L-talopyranan by selective ring-opening polymerization of 1,4-anhydro sugar derivatives, Macromolecules, 24 (1991) 987-992. 

Y. S. Choi, T. Uryu, and T. Yoshida, Synthesis of block copolysaccharides by ring-opening polymerization of anhydro sugar derivatives, Macromol. Chem. Phys., 198 (1997) 2875-2888. 

T. Uryu, K. Kitano, and K. Matsuzaki, Ring-opening polymerization of 5,6-anhydro-glucose and 5,6-anhydro-allose derivatives. Effect of substitution or configurational difference at the position of sugar monomers on polymerization behavior, J. Polym. Sci., Part A Polym. Chem., 20 (1982) 2181-2194. 

Polylactide is a degradable polyester, formed by the ring-opening polymerization of lactide or the condensation polymerization of lactic acid. Lactide is produced from lactic acid, which derives from the fermentation of D-glucose, which is usually harvested from high-starch-content crops, such as com or sugar beet (Fig. 1). 

Polysaccharides arise from monomeric sugars by elimination of water, i.e., either by polycondensation of sugars or ring-opening polymerization of anhydro sugars ... 

Shen Y., Chen X., Gross R.A., Polycarbonates from sugars Ring opening polymerization of 1,2-0-isopropylidene-D-xylofuranose-3,5-cyclic carbonate (IPXTC), Macromolecules, 32, 1999, 2799-2802. 

PLA can be produced by condensation polymerization directly from its basic building block lactic acid, which is derived by fermentation of sugars from carbohydrate sources such as com, sugarcane, or tapioca, as will be discussed later in this chapter. Most commercial routes, however, utilize the more efficient conversion of lactide—the cyclic dimer of lactic acid— to PLA via ring-opening polymerization (ROP) catalyzed by a Sn(ll)-based catalyst rather than polycondensation [2-6]. Both polymerization concepts rely on highly concentrated polymer-grade lactic acid of excellent quality... 

Poly(L-lactide) (PLLA) is a biodegradable aliphatic polyester produced by ring-opening polymerization of lactide (i.e., with cyclic dimer of lactic acid) or by polycondensation of lactic acid. Although PLLA is a synthetic polymer, it is considered a renewable and bio-based plastic because its raw material lactic acid is synthesized from biomass or renewable resources such as sugars and starch. PLLA has some properties that are similar to some petroleum-based plastics, thereby making it suitable for a variety of applications in the medical, textile, and packaging industries. 

Schlaad and coworkers " applied another click reaction for glycoconjugation - the thiol-ene reaction. They first synthesized a well-defined poly[2(-3-isobutenyl)-2-oxazoline] scaffold via cationic ring opening polymerization, which was then followed hy the addition of sugar thiols such as acetylated thioglucose via photoaddition to the polymeric vinyl groups (Figure 2.12). 

Poly(lactic acid) (PLA) is produced from the monomer of lactic acid (LA). PLA can be produced by two well-known processes — the direct polycondensation (DP) route and the ring-opening polymerization (ROP) route. Although DP is simpler than ROP for the production of PLA, ROP can produce a low-molecular-weight brittle form of PLA. Generally, several substances are involved in the production of PLA, and these relationships have been summarized in Figure 2.1. The lactic acid for the process is obtained from the fermentation of sugar. Lactic acid is converted to lactide and eventually to PLA. It should be noted that there are two different terms, poly(lactic acid) and polylactide , for the polymer of lactic acid. Both terms are used... 

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