0000007587 00000 n Polymers can be synthesized as either random or block copolymers thereby imparting additional polymer prop… endstream endobj 54 0 obj<> endobj 56 0 obj<>/Font<>>>/DA(/Helv 0 Tf 0 g )>> endobj 57 0 obj<> endobj 58 0 obj<> endobj 59 0 obj<>/ProcSet[/PDF/Text]/ExtGState<>>> endobj 60 0 obj<> endobj 61 0 obj<> endobj 62 0 obj<> endobj 63 0 obj<> endobj 64 0 obj<> endobj 65 0 obj<> endobj 66 0 obj<> endobj 67 0 obj<>stream 0000008681 00000 n Depending on the ratio of lactide to glycolide used for the polymerization, different forms of PLGA can be obtained: these are usually identified in regard to the molar ratio of the monomers used (e.g. The properties of PLA improved tremendously with the development of production using ring-opening polymerization. Reproduced with permission from Elsevier Ltd. 5.13) [14]. The electrical conductivity of the material can be calculated indirectly by two-probe method, which measures volume resistivity (Ω.cm) and represents resistance of the composite material denoted by the unit volume (1 cm × 1 cm × 1 cm) [14,15]. *Please select more than one item to compare This device directly gives the value of thermal flux through flowmeter available on both sides and temperature gradient by two thermocouples. Fig. 0000023230 00000 n PLA is a crystalline thermoplastic having a melting point of 130–180 °C. The equipment was designed to measure the thermal conductivity of samples with 2 mm thickness. 4.1 and 4.2 are showing the influence of the crystallinity on the macroscopic behavior. [4] Since the body can metabolize the two monomers, there is minimal systemic toxicity associated with using PLGA for biomaterial applications.

The lactic acid used is yielded from the fermentation of carbohydrates such as starch and cellulose. Compare Products: Select up to 4 products.

The addition of graphite content in hybrid blend leads to high thermal conductivity and increase in CNT amount proceeds high viscous nature of blends to encounter processing difficulty are the possible limitations for increasing the filler concentration (Fig. This route requires an intermediate substance known as lactide. The maximization of ZT value for thermoelectric materials through refining of grain sizes which scatters the grain boundary leads to the reduction in thermal conductivity.
For the most part, the direct polycondensation route (Fig.

[2] This flexibility in degradation has made it convenient for fabrication of many medical devices, such as, grafts, sutures, implants, prosthetic devices, surgical sealant films, micro and nanoparticles. The main properties from material datasheet are described in Table 4.3. The chapter then describes the properties and structure of PLA fibres, and their potential applications. The drawback is that it increases the electrical resistivity of the material. Generally, the performance of composite materials will be greater than the materials with monotonous fine or coarse grains. https://doi.org/10.1533/9781845696504.2.257. 0000011204 00000 n PLGA, PLG, or poly(lactic-co-glycolic acid) is a copolymer which is used in a host of Food and Drug Administration (FDA) approved therapeutic devices, owing to its biodegradability and biocompatibility. 0000005956 00000 n 0000005060 00000 n Due to its excellent strength properties, film transparency, biodegradability, biocompatibility, and availability from renewable sources, PLA is commercially attractive. 434 Polylactic Acid: Synthesis, Properties and Applications, L. Avérous PLA belongs to the family of aliphatic polyesters commonly made from -hydroxy acids, which also includes, for example, polyglycolic acid (PGA). The resultant PLA had a low molecular weight and poor mechanical properties. where λ is the thermal conductivity, e is the thickness of sample, φ is the thermal flux between the sample sides, and ΔT is the temperature gradient. The properties of PLA are determined by the polymer architecture (i.e., the stereochemical makeup of the backbone) and the molecular mass, which is controlled by the addition of hydroxylic compounds. Table 4.3. NatureWorks’ PLA is produced mainly for biodegradable packaging, containers, clothing, fibers, etc. In addition, polymers that are end-capped with esters (as opposed to the free carboxylic acid) demonstrate longer degradation half-lives. 5.11.

Poly(lactic acid)-CNT-GR, PLA-CNT, PLA-GR blend were prepared using brabender to form a polymer composite and thermoelectric behavior of each composite was studied to understand the effect of fillers on biopolymer. 6.3 Syndiotactic polymerization and syndiotacticity. 0000009507 00000 n Figure 5.10. Copyright 2011. Polylactic Acid (PLA) is a bioplastic generally derived from animal-feed corn that can be used for a myriad of different purposes including cold drink cups, deli and takeout containers, and fresh produce packaging.

It should serve as an excellent compilation for researchers and prospective researchers in this growing field of polymer chemistry. Polylactic acid polymers are creating a lot of interest these days because they're biodegradable. An exception to this rule is the copolymer with 50:50 monomers' ratio which exhibits the faster degradation (about two months). Lactic acid is metabolized in the tricarboxylic acid cycle and eliminated via carbon dioxide and water. 53 0 obj<> endobj The typical experimental set-up shown here was used to measure the thermal conductivity of biopolymer composite by guarded hot plate method.