Polylactic acid functionalized polymers

This chapter deals with polymers synthesized from oilseed sources. However, to provide the reader with an appreciation of the area of renewable, biodegradable polymers and the place within this area that polymers from oil seeds occupy in terms of functionality, price, and acceptability, some other polymers from major renewable sources are also discussed. The most well-known and widely used renewable biodegradable polymers are those from polysaccharides. The principal polysaccharides of interest to polymer chemists are starches and cellulose, both of which are polymers of glucose. In addition to these, fibers, polylactic acid (PLA), and triacylglycerols of oils are of particular interest for the development of biodegradable industrial polymers. 

Polyorthoesters, polyanhydrides, and combinations of polyglycolic and polylactic acid were all tested. Again, our most satisfactory results were obtained initially when the polymers consisted of fiber networks with a fiber diameter of 14-15 microns. We began to identify features of a substrate to which the cells were anchored which were important for maintaining cell function, and incorporate them into the polymer matrix used for transplantation. 

In the category of the polymers produced from bio-based monomers, the polyesters used to be more popular. Thus, historically, the main studied monomers were bi-functional molecules, such as lactic acid, an a-hydrmy acid able to self-condense for the production of polylactic acid (PLA) 1.3-propanediol (PDO) leading to Dupont s Sorona after condensation with terephthalic acid and succinic acid, foreseen to be a key bio-based building block and leading to polybutylene succinate (PBS) after condensation with 1,4-butanediol. 

Reinforced matrix scaffold for tissue engineering Some biomaterials, like naturally derived materials (eg, type I collagen, alginate) or synthetic polymers (eg, poly-glycolic acid (PGA), polylactic acid (PLA)), are commonly used for tissue engineering as 3D scaffolds whose primary function is to control the geometry and the volume of... 

Fama LM, Pettarin V, Goyanes S, Bernal CR (2011) Starch based nanocomposites with improved mechanical properties. Carbohydr Polym 83 1226-1231 Fama LM, Ganan P, Bernal CR, Goyanes S (2012) Biodegradable starch nanocomposites with low water vapor permeability and high storage modulus. Carbohydr Polym 87 1989-1993 Fama L, Kumar R (2014) Nanocomposites based on polylactic acid (PLA) reinforced by functionalized carbon nanotubes (CNT). In Kumar R (ed) Polymer-matrix composites t3fpes, applications and performance. Nova Science Publishers, Inc. USA (in press)... 

Ester bond-hastd polymers, called polyesters, include several biodegradable and nonbiodegradable polymers such as polyethylene terephthalate (PET), polybutylene terephthalate, polybutylene succinate, polycaprolactone, polylactic acid, polyhydroxyalcanoate and aromatic-aliphatic polyesters. They are derived from starting monomers such as dialcohol, diacid and/or their esters (like methyl esters), and hydroxyl acids that are monomers with both an alcoholic and a carboxylic functional group. All such monomers react to form ester bonds with the release of water (or methanol if the starting monomers are the methylic esters of diacids). 

We felt that the physicochemical properties of the polymer might therefore be manipulated to alter the cell shape and thus the cell physiology. We next studied the effects of polymers of different physical and chemical configuration on cell attachment, viability and performance of differentiated function. The ability of the hepatocyte to maintain differentiated function was assessed by Ae rate of albumin secretion. We found that a suitable polymer was an uncoated 85 15 combination of polylactic/polyglycolic acid. This suggested to us that a... 

Alternatively to the use of hpids for the development of deUvery systems, polymeric materials can be also used as building blocks. As with Upid-based delivery systems for nucleic acids, polymers were first used in gaie deUvery as a part of the development of new DNA transfection vectors (Wu and Wu, 1987). Polymers can be synthesized in different lengths, with different geometry (linear versus branched), and with substitution or addition of functional groups. As such, there is a wide variety of natural and synthetic polymers currently used for siRNA and DNA deUvery, such as chitosan (Yao et al., 2015), polylactic-co-glycoUc acid (Lee et al., 2011), or polyethylenimine (PEI Francis et al., 2014). 

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