Polybutylene terephthalate structure

Figure 6.2 The polyesteramide structure proposed by Gaymans and co-workers E, ester group A, amide group [21]. Reprinted from Polymer, 38, van Bennekom, A. C. M. and Gaymans, R. J., Amide-modified polybutylene terephthalate structure and properties, 657-665, Copyright (1997), with permission from Elsevier Science...

Polyesters form via a condensation reaction between a dicarboxylic acid and a dialcohol to create an ester linkage, as shown in Fig. 24.1. By far, the two most common polyesters are polyethylene terephthalate and polybutylene terephthalate, the chemical structures of which are shown in Fig. 24.2. These two polymers differ from one another by the length... 

Cheng, Y.-Y., Brillhart, M., Cebe, P. and Capel, M., X-ray scattering and thermal analysis study of the effects of molecular weight on phase structure in blends of polybutylene terephthalate with polycarbonate, J. Poly. Sci., Polym. Phys., 34, 2953-2965 (1996). 

Polybutylene terephthalate Figure 153. Structures of terephthalate esters. 

Most polymers fall in the class of translucent resins. These include acetal, polyamide, polybutylene terephthalate (PBT), polyethylene, and polypropylene as examples. There are very few neat polymers that are truly opaque (this depends on thickness as well). Liquid crystal polymer (LCP) is an example of a typically opaque polymer. It is theorized that these semicrystalline and crystalline resins will scatter some portion of incident light due to spherulitic crystal structure and the amorphous-crystalline region interfaces themselves. 

The popular thermoplastic polyesters are polybutylene terephthalate (PBT) and polyethylene terephthalate (PET). TP polyesters are in a family of polyesters that has widely varying and important range of properties. There are the two major groups of the TPs (with comparatively high melting points) and the TSs (which are usually typified by a cross-linked structure). TP polyesters are often called saturated polyesters to distinguish them from unsaturated polyesters that are the TSs. 

Polybutylene Terephthalate (PBT). With the expiration of the original PET patents, manufacturers pursued the polymerization of other polyalkene teiephthalates, particularly polybutylene terephthalate (PBT). The polymer is synthesized by reacting terephthalic acid with butane 1,4-diol to yield the structure shown in Fig. 2.16. 

When polybutylene terephthalate and polyethylene terephthalate degrade under the influence of light, photo-induced reactions are observed such as Norrish type I and type II (see Figure 5.12) and photo-oxidative processes. Figure 5.88. The formation of m-biphenyl structures can also be detected [38]. 

The majority of fiber-forming polymers, like common plastics, are based on petrochemical sources. Polymeric fibers can be produced from the following materials polyamide nylon, polyethylene terephthalate (PET) or polybutylene terephthalate (PBT) polyesters, phenol-formaldehyde (PF), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), and polyolefins (polypropylene (PP) and polyethylene (PE)) among others. Because of the different chemical structures of fiber-forming polymers, their applications vary widely according to the temperature and chemical conditions which they can withstand. For example, polyethylene melts into a viscous liquid at temperatures equal to or less than that of a domestic dryer and therefore its application in a product that will require normal laundering is not possible. However, its fibers can be used in making disposable non-woven products. ... 

The matrix is a biodegradable and aromatic copolyester (polybutylene adipate-co-terephthalate, PBAT), from Eastman (EASTAR BIO Ultra Copolyester 14766). Copolyester chemical structure is given in Table 17.2. This copolyester is soluble at room temperature in different solvents such as THF, CH2CI2, or CHCI3. Determined by HNMR, PBAT composition is 43% of butylene terephthalate and 57% of butylene adipate. Determined by size exclusion chromatography (SEC), molecular weight (Mw) and polydispersity index (IP) are 48,000 and 2.4, respectively. Melt flow index (MFI) is 13 g/10 min at 190°C/2.16 Kg. PBAT density is 1.27 g/cm at 23°C. 

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