Poly butylene adipate Copolyesters

Ecoflex F, the original Ecoflex grade, is a completely fossil-based ahphatic-aromatic copolyester produced by BASF (see Sect. 4). It is synthesized from 1,4-butanediol, adipic acid and terephthalic acid, and is a poly(butylene adipate-co-butylene terephthalate) (PBAT). 

Figure 21.9 The biodegradable polyester family poly(hydroxyalkanoates) (PHA), poly(hydroxybulyrate) (PHB), poly(hydro3qdiexanoate) (PHH), poly(hydrox3rvalerate] (PHV), polyflactic acid) (PLA), poly(caprolactone) fPCL), poly(butylene succinate) (PBS), poly(butylene succinate adipate) (PBSA), aliphatic-aromatic copolyesters (AAC), poly(ethylene terephthalate) (PET), poly(butylene adipate/terephthalate) (PBAT), poly(methylene adipate/terephthalate) (PTMAT). Adapted from [103].

EastarBio copolyester (4), (Table 1), manufactured by Eastman Chemical, is a random poly(butylene adipate-co-terephthalate) containing 50% terephthalate film is prepared by solvent casting (Fig. 1). EastarBio copolyester biodegrades to the extent of 80% in 150 days in a compost environment. 

Ecoflex (poly(butylene adipate-co-terephthalate)), a commercialized aliphahc-aromatic copolyester from BASF, was characterized to be an ideal random copofymer with 44 mol% of BT units. The glass transition occurs at 30°C, and the melting point is 110-115°C [86]. The physical and mechanical properties of this soft thermoplastic are similar to those of LDPE, and it can be processed on convenhonal equipment for LDPE. 

Gan Z., Kuwabara K., Yamamoto M., Abe H., Doi Y Solid-state and thermal properties of aliphatic-aromatic poly(butylene adipate-co-butylene terephthalate) copolyesters., Polym. Deg. Stab. 83 (2004) 289. 

PLA), polycaprolactone (PCL), aliphatic copolyesteis (poly(butylene succinate), poly(butylene succinate-co-adipate), poly(ethylene succinate)), aliphatic-aromatic copolyesters (poly(butylene adipate-co-terephthalate)), starch-based polymers, polyCvii rl alcohol), cellulose acetate. 

Poly(butylene adipate-co-succinate)/poly(butylene terephthalate) copolyesters prepared by the transesterification reaction of PBAS and PBT were characterized [93]. The biodegradability of copolyesters depended on the terephthalate unit in the composition and average block length of the aromatic unit. 

Kang H.X, Park S.S. Characterization and biodegradability of poly(butylene adipate-co-succi-nate)/poly(butylene terephthalate) copolyester, J. Appl. Polym. Sci. 72 (1999) 593. 

Poly (butylene adipate-co-terephthalate) (PBAT) is an interesting polymer [116,117] and has attracted more attention. PBAT is also a biodegradable poljmier, which has proper viscosity and elasticity. Moreover, the balance of biodegradability (e.g., life time) and its physical properties (e.g., thermal and mechanical properties) can be adjusted by controlling the molar ratio of comonomers in the copolymer [118,119]. It has been reported that the aliphatic/aromatic copolyester with aromatic units within the range of 35 - 55 mol% offers an optimal compromise of its biodegradability and physical properties. 

AAC -Aliphatic-Aromatic Copolyesters PBAT - Poly(Butylene Adipate/Terephthalate)... 

An extensive investigation on the anaerobic degradability of a number of natural and synthetic polyesters was performed by Abou-Zeid [30]. Beside the poly(hydroxyalkanoates), PHB and PHBV (10 mol% HV) she tested PCL, the aliphatic homopolyester poly(butylene adipate) (SP4/6) and the copolyester poly(butylene adipate-co-butylene terephthalate) where about 40% of the diacid component consists of the aromatic terephthalic acid (BTA 40 60). Weight loss measurements of polymer films (40-74 pm thickness) in two different... 

Biodegradable polymers can also be produced from petroleum sources and are comprised of aliphatic polyesters and copolyesters (e.g., PBS, and poly(butylene succinate adipate)—PBSA), aromatic copolyesters (e.g., poly(butylene adipate terephthalate)—PBAT), poly(e-caprolactone) PCL, polyesteramides (PEA), and poly(vinyl alcohol) (PVA). Further details concerning the synthesis of these polymers can be found in the book by Rudnik (2008). In this section we summarize some of the key properties of these materials... 

A different approach consists of reacting dimethyl terephthalate and dimediyl adipate with 1,4-butanediol in die experimental conditions of poly(butylene terephthalate) (PBT) syndiesis. The resulting copolyester (Eastman s Eastar Bio) presents properties close to diose of odier degradable materials (Table 2.10). 

It is of particular interest that PBS has a higher hydrolytic degradation rate than poly(butylene succinate-co-butylene adipate) (PBSA) copolymers, as shown in Fig. 17 (Ahn et al. 2001). It is suggested that the presence of butylene adipate units may promote the hydrophobic nature of copolyesters, which would negatively influence the hydrolytic susceptibility by sterically hindering the access of nucleophiles. 

PHBV - poly-(3-hydroxybutyrate-co-3-valerate), Monsanto (Biopol D400G, HV 7%) PLA - polyOactic acid), Dow-Cargill (Nature Works) PCL - polycaprolactone, Solvay (CAPA 680) PEA - polyesteramide, Bayer (BAK 1095) PBSA - poly(butylene succinate-co-adipate), Showa (Bionolle 3000) PBAT - aromatic copolyester, Eastman (Eastar bio 14766). 

Poly(butylene succinate-co-adipate)/PLA Blends Poly(butylene succinate adipate), poly(butylene succinate-co-adipate), or poly(butylene succinate-co-butyl-ene adipate) (PBSA) is a random aliphatic copolyester comprised of 1,4-butanediol, succinic acid, and adipic acid [157]. PBSA has lower thermal properties (Tg of —45°C, Tc of 50-53°C, I m of 93-95°C, crystallinity of 20-35%, and HDT at 0.45 MPa of 69°C), more flexibility (tensile strength of 34 7 MPa, tensile elongation of 400-900%, and flexural modulus of 323-340 MPa), and a faster biodegradation rate than PBS [142, 157]. PBSA/PLA blends are immiscible, and a complicated cocontinuous phase (domains of the other polymers dispersed in each continuous phase) was observed... 

Aliphatic polyesters and copolyesters (e.g. poly(butylene succinate) - PBS poly (butylene snccinate adipate) - PBSA). 

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