Copolyesters were synthesized through the condensation of 0.0025 mol of 1,1 0 -bis(3-methyl-4-hydroxyphenyl)cyclohexane, 0.0025 mol of ethylene glycol/propylene glycol/1,4-butanediol/1,6-hexane diol, and 0.005 mol of terephthaloyl chloride with water/chloroform (4:1 v/v) as an interphase, 0.0125 mol of sodium hydroxide as an acid acceptor, and 50 mg of cetyl trimethyl ammonium bromide as an emulsifier. The reaction time and temperature were 2 h and 08C, respectively. The yields of the copolyesters were 81-96%. The structures of the copolyesters were supported by Fourier transform infrared and 1 H-NMR spectral data and were characterized with the solution viscosity and density by a floatation method (1.1011-1.2697 g/cm 3 ). Both the intrinsic viscosity and density of the copolyesters decreased with the nature and alkyl chain length of the diol. The copolyesters possessed fairly good hydrolytic stability against water and 10% solutions of acids, alkalis, and salts at room temperature. The copolyesters possessed moderate-to-good tensile strength (11-37.5 MPa), good-to-excellent electric strength (19-45.6 kV/mm), excellent volume resistivity (3.8 3 1015 to 2.56 3 10 17 O cm), and high glass-transition temperatures (148-1958C) and were thermally stable up to about 408-4278C in a nitrogen atmosphere; they followed single-step degradation kinetics involving 38-58% weight losses and 34-59% residues. The copolyesters followed 2.6-2.9-order degradation kinetics.
Polyvinylalcohol (PVA) and Polyvinylpyrrolidone (PVP) blend incorporated with hydroxyapatite (HAp) and β-tricalcium phosphate (β-TCP) is electrospun as nanofibrous composite scaffolds to act as suitable template for bone tissue engineering. Microscopic and spectroscopic characterizations confirm uniform integration of the crystalline calcium phosphate ceramics in the scaffolds. PVA-PVP blends are usually amorphous in nature and addition of phosphate ceramic particles specifically HAp elevates its crystalline behavior which is substantiated by XRD details. Further incorporation of ceramics is confirmed using FT-IR as characteristic PO43- groups for HAp and β-TCP were observed in the distinguished composites. Single glass transition temperature is observed for pure and composite blends indicating the formation of highly miscible blends. Also, addition of these ceramics augments the thermal stability of the blend scaffolds. Biocompatibility of the prepared (PVA: PVP)-HAp and (PVA: PVP)-TCP scaffolds is assessed using MG-63 Osteoblast cell lines in the time interval of 1st, 4th and 7th day. The cell viability percentage for (PVA: PVP)-HAp is high compared to β-TCP added blend composites, reinforcing the fact that scaffolds with good mechanical strength and enhanced porosity supports better cell adhesion.
β Tricalcium phosphate ceramic was used to reinforce nanofibers in composite mats produced via electrospinning of poly(vinyl alcohol) (PVA), polycaprolactone (PCL) and (PVA: PCL) bilayers. The role of TCP ceramic on morphology of nanocomposites, crystalline structure, functional groups and thermal behaviour of nanocomposites were characterized by SEM, EDAX, XRD, FTIR and DSC analysis. Ultrathin cross-sections of the obtained nanocomposites were morphologically investigated with SEM and all fabricated composites consisted of fibers with average fiber diameter (AFD) around 100 nm except PCL-TCP fibers having AFD in the range of 608 nm. XRD profile presented the main peaks of β-TCP (JCPDS 090169 and JCPDS 70-2065). The characteristic absorption bands of TCP were also identified by FTIR in all the composites. The thermal stability was enhanced after adding TCP filler particles in all the polymer composites. The porosity of PCL-TCP was found around 63% and (PVA-PCL: TCP) composite was found to be 58%. The biocompatibility of the (PVA-PCL: TCP) composite scaffold has also been investigated by culturing MG-63 osteoblast cells on it; primary results showed that the cells adhered and proliferated well on the composite scaffold.
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