Polyglycolic acid Polymerization

Ring-Opening Polymerization Polylactic Acid, Polyglycolic Acid, and Polycaprolactone... 

They are made of polymeric, waxy, or other protective materials, that is, biodegradable synthetic polymers and modified natural products such as starches, gums, proteins, fats, and waxes. The natural polymers include albumin and gelatin " the synthetic polymers include polylactic acid and polyglycolic acid. ... 

A review is presented on the controlled release of calcitonins from polymeric matrices and oil-based formulations covering the period 1992-8. Polymers covered include biodegradable polymers, such as polyglycolic acid, polylactic acid and copolymers thereof, and non-biodegradable polymers, such as styrene-isopropyl acrylamide copolymers and poly(methacrylic acid-g-ethylene glycol) copolymers, for oral calcitonin delivery systems. 28 refs. 

Polyhydroxy acids are another group of biopolymers. Since polylactic acids, polyglycolic acid, and poly(citric acid) are classified as thermoplastic polyesters (saturated), they lack reactive functional groups for surface reactions. Moreover, any chemical manipulation to create activation sites results in hydrolysis of the ester bonds. The only reported successful methods for functionalization of polyhydroxy acids are blending them with ECPs, or using a plasma polymerization process [29]. Prior to the plasma polymerization process, surface activation or ionization of these biopolymers must be carried out, which is acquired by means of vapor phase deposition, laser deposition, microwave or synchrotron radiation [30], pulsed arc, pulsed combustion, spark, or friction induction [30], electron beams, plasma induction, corona, photons, ion beams, and X-rays [25]. 

The synthetic absorbable sutures are made from polymers capable of degradation in the biological environment without adverse effects. One overall advantage of absorbable sutures is the elimination of clinical visits for their removal. These sutures are either homopolymers or copolymers based on degradable polymeric units such as polyglycolic acid, polylactic acid, or poly-/ -dioxanone. 

More interest has been shown in polymeric flexibilisers, particularly the low molecular weight polyamides from dimer acid (see Chapter 18), the low molecular weight poly sulphides (Chapter 19), polyamines and the polyglycol diepoxides. 

As a preliminary step in the manufacture of unsaturated polyester thermoset plastic one uses low molecular weight linear polyester (Mr 10,000) obtained by a polycondensation of polyglycols with saturated and unsaturated dicarboxylic acids. The precondensate can then be dissolved and stored in the stabilized comonomer, e.g. styrene, with which it will be crosslinked later. The crosslinking polymerization reaction between the polyester chains and the styrene bridges is initiated with the help of organic peroxides which are added dispersed in plasticizers. The reaction begins at 60-90 °C and then proceeds exothermally. In addition to this a cold hardening reaction can also be carried out. For this reaction cold accelerators are necessary, e.g. tertiary amines or cobalt naphthenate. 

Polyglycol mono oleate Polyhydrocarboxylic acid salt Polymeric alcohol blend Polymeric blend Polymethyl naphthalene sulphonate sodium salt Polyolefin... 

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