Synthesis, characterization, and properties of degradable poly(l‐lactic acid)/poly(butylene terephthalate) copolyesters containing 1,4‐cyclohexanedimethanol

Abstract

High-molecular-weight copolyesters based on poly(butylene terephthalate) as rigid aromatic segments and poly(l-lactic acid) (PLLA) as degradable aliphatic segments were synthesized via the polycondensation of terephthalic acid, 1,4-butanediol (BDO), 1,4-cyclohexanedimethanol (CHDM), and PLLA oligomer. By tailoring the molar ratio of diols (BDO and CHDM), we investigated in detail the effects of the CHDM rigid hexacyclic ring on the synthesis, mechanical properties, thermal stabilities, and degradation behaviors of the copolyesters. With increasing CHDM content, the initial decomposition temperature increased from 282.5 to 322.2 C, and the tensile strength improved by nearly four times, from 5.4 to 19 MPa. When the molar ratio of BDO/CHDM was 95/5, the weight-average molecular weight of the copolyester was 89,400 g/mol with a polydispersity of 1.96. In addition, hydrolytic degradation results in phosphate buffer solution indicate that the degradation rate of the copolyesters displayed a strong dependency on the temperature and CHDM composition.

Synthesis and properties of novel water‐dispersible polyisocyanates

“…Meanwhile, the hydrophilicity of WDPs and its compatibility with hydroxyl component was decreased, resulting in declined transparency and gloss of the films. Consistent with previous reports, the introduction of CHDM could improve the hardness and resistance of films efficiently due to the rigid ring structures and hydrophobicity of CHDM. However, when the contents of CHDM increased to two third molars of MPEG, the water dispersibility of WDP became so poor that WDP could hardly be dispersed stably and could not react fully with hydroxyl components.…”

“…Besides, a slight increase in all the decomposition temperature was observed in film based on WDP ( C 3 ) compared with that of WDP ( C 1 ). This indicated that a small amount addition of the thermally stable cyclic CHDM unit slightly improved the thermal stability of the 2K‐WPU films …”

Preparation, characterization, and properties of novel biodegradable aliphatic–aromatic copolyester nanohybrids with polyhedral oligomeric silsesquioxanes moieties

“…Probable structures of the nanohybrid are shown in Figure 4, and their corresponding characteristic peaks are shown in Figure 5. The peaks centered at 8.10, 4.42, and 1.97 ppm were assigned to the protons (H 1 ) of the benzene ring, OCH 2 (H 4 ), and adjacent CH 2 (H 14 ) of butylene terephthalate moiety, respectively, whereas the signals at 4.36–4.22 ppm corresponded to OCH 2 (H5–10) of butylenedioxy and ethylenedioxy, which covalently linked to terephthalate, BH‐POSS, and/or lactate. Lactate units had two characteristic peaks at 5.18 and 1.54 ppm, which were attributed to the CH (H 3 ) and CH 3 (H 20 ), respectively.…”

“…On the other hand, aliphatic polyesters, such as poly(caprolactone), poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and poly(hydroxybutyrate) (PHB), are considered to be an important class of biodegradable polymers and could be degraded under natural conditions, but they are usually high cost and had relatively poor physical and mechanical properties 2, 3. To optimize biodegradability and mechanical properties, incorporating biodegradable aliphatic polyesters into main chains of aromatic polyesters has been regarded as an attractive approach to obtain novel materials encompassing with high physical properties and good biodegradability 4–6. Aliphatic–aromatic copolyesters such as poly(butylene adipate)/PBT, poly(ethylene succinate)/PET, poly(butylene adipate‐ co ‐succinate)/PBT, PHB/PET, and PBS/PBT have been reported to show degradabiliy to some extent depending on the content and random degree of aliphatic polyester segments 7–11…”

Effect of segment structures on the hydrolytic degradation behaviors of totally degradable poly(L‐lactic acid)‐based copolymers

“…Hence, it is of great importance to accelerate the hydrolytic degradation rate of P L LA and more desirably to be able to match the implant degradation rate with the healing rate of the wound. Among various methods to achieve the goal, copolymerization is an efficient approach, which can both tailor the degradation rate and enhance the mechanical properties of the polymer …”