Phase separation and physical properties of PEO-containing poly(ether ester amide)s

Shi

et al. 2007

Thermoplastic poly(glycerol sebacate) (TMPGS) elastomers originating from three prepolymers with different molecular weights were prepared first, and then the structure and properties were studied. Specifically, by swelling tests, gel permeation chromatography, X-ray diffraction, and differential scanning calorimetry, the crosslinking densities, sol contents and compositions, crystallization, and thermal performances of three TMPGSs were examined. Finally, the degradability in a 378C phosphate-buffered saline solution (pH ¼ 7.4) was also illuminated. The three TMPGSs had similar chemical structures, but the different molecular weights of the prepolymers influenced their final compositions and properties to a great extent. Furthermore, both hydrogen bonding and plasticization action in the elastomers played important roles in balancing the overall properties of the TMPGS elastomers.

Section: Mechanical Performance Ordered Structure and Thermal Propementioning

confidence: 99%

“…Thermoplastic elastomers are usually phase-separated block copolymers, [1][2][3] whereas thermoset elastomers are formed sometimes by the crosslinking of starshaped prepolymers. [4][5][6][7][8] Thermoplastic and thermoset elastomers can be prepared by special methods.…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of thermoplastic poly(glycerol sebacate) elastomers originating from prepolymers with different molecular weights

Shi

et al. 2007

“…14 Biodegradable elastomers are generally of two types: thermoplastic elastomers and thermoset elastomers. Thermoplastic elastomers are usually phaseseparated block copolymers, [15][16][17] while thermoset elastomers are the products sometimes formed after crosslinking of the star-shaped prepolymers. [18][19][20][21][22] Thermoplastic elastomers are easily fabricated by melting processing; however, the crystallized hard regions possessed by these materials slow their biodegradation, and the remaining dimension is poor.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of a thermoplastic poly(glycerol sebacate) elastomer by two‐step method

Ding

et al. 2006

A thermoplastic poly(glycerol sebacate) elastomer (TMPGS), prepared by a two-step method for the first time, is characterized in the present work. First, non-crosslinked poly(glycerol sebacate) (PGS) prepolymers at the 1 : 1 molar ratio of glycerol to sebacic acid were synthesized through a condensation reaction. Second, TMPGSs were achieved through prepolymers that continued to react after the addition of more sebacic acid at a total molar ratio of 2 : 2.5 (glycerol/sebacic acid). The swelling experiments demonstrated that its crosslinking density was low and that it was composed of sol and gel. Compared with our previous results, the content of sol decreased but still reached >60%. Differential scanning calorimetry (DSC) studies demonstrated that TMPGS was crystallizable and had a glass transition temperature below À208C, but at close to 378C, its state altered and became almost amorphous. It was explained that both the semi-interpenetrated polymer networks composed of sol and gel and the crystal regions imparted thermoplasticity to the elastomer. Finally, the in vitro degradation tests illuminated the degradation characteristic of TMPGS in 378C phosphate buffered saline solution (pH ¼ 7.4).

“…3,4 Biodegradable elastomers can be tailored within wide ranges, which allows them to be used in many surgical applications in both soft and hard tissues because of their adjustable physical properties, especially their good flexibility. [5][6][7][8][9] Biodegradable elastomers have usually been prepared as one of two types: thermoplastic elastomers or thermoset elastomers. Thermoplastic elastomers are usually phase-separated block copolymers 7,10,11 consisting of soft, rubber-like segments [with a low glasstransition temperature (T g )], which impart flexibility to the materials, and glassy or crystallizable segments, which provide strength and stiffness by the formation of a hard phase; these include the segmented polyurethanes, poly(ethylene oxide) and poly(butylenes terephthalate), and segmented poly(ether ester amide).…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of a biodegradable polyester elastomer with thermal processing abilities

Ding

et al. 2005

ABSTRACT:We studied the condensing reaction of sebacic acid and glycerol and prepared biodegradable elastomers. Swelling experiments proved that the elastomers were crosslinked polyesters consisting of both insoluble parts (gel) and soluble parts (sol), but the content of sol was higher than gel. X-ray diffraction analysis showed that some ordered and crystallized structures existed in most of the elastomers. Differential scanning calorimetry measurement showed that there were both crystal regions and amorphous regions with low glass-transition temperatures in the products, which indicated the elastomers had a microphase separation structure. The elastomers exhibited thermal processing abilities, such as mold-shaping performance, and a certain elasticity, and hydroxyl, carboxyl, and ester groups in the molecular chains endowed the elastomers with good biodegradation abilities. Furthermore, by altering the molar ratio of the reactants, we were able to adjust the mechanical properties, biodegradable performance, and so on of the elastomers. Glycerol and polymers containing sebacic acid have been approved for biological medical uses by the U.S. Food and Drug Administration, so the elastomers we prepared would have broad application in medical fields such as implants and drug-delivery systems.