Antimicromial and antioxidant bioactive films based on poly(lactic acid)/poly(trimenthylene carbonate) films incorporated with different concentrations of oregano essential oil (OEO) were prepared by solvent casting. The antimicrobial, antioxidant, physical, thermal, microstructural, and mechanical properties of the resulting films were examined. Scanning electron microscopy analysis revealed that the cross-section of films became rougher when OEO was incorporated into PLA/PTMC blends. Differential scanning calorimetry analysis indicated that crystallinity of PLA phase decreased by the addition of OEO, but this did not affect the thermal stability of the films. Water vapor permeability of films slightly increased with increasing concentration of OEO. However, active PLA/PTMC/OEO composite films showed adequate barrier properties for food packaging application. The antimicrobial and antioxidant capacities were significantly improved with the incorporation of OEO (p < 0.05). The results demonstrated that an optimal balance between the mechanical, barrier, thermal, antioxidant, and antimicrobial properties of the films was achieved by the incorporation of 9 wt % OEO into PLA/PTMC blends.
An efficient and catalyst-free synthesis of trisubstituted allylic sulfones through an allylic sulfonylation reaction of Morita-Baylis-Hillman (MBH) carbonates with sodium sulfinates has been developed. Under the optimized reaction conditions, a series of trisubstituted allylic sulfones were rapidly prepared in good to excellent yields (71%–99%) with good to high selectivity (Z/E from 79:21 to >99:1). Compared with known synthetic methods, the current protocol features mild reaction temperature, high efficiency and easily available reagents.
In this study, hydroxyapatite (HAP) was surface-modified by the addition of β-alanine (β-Ala), and the ring-opening polymerization of γ-benzyl-L-glutamate-N-carboxy-anhydride (BLG-NCA) was subsequently initiated. HAP containing surface poly-γ-benzyl-L-glutamates (PBLG) was successfully prepared in this way. With the increase of PBLG content in HAP-PBLG, the solubility of HAP-PBLG increased gradually and it was ultimately soluble in chloroform. HAP-PLGA with surface carboxyl groups was obtained by the catalytic hydrogenation of HAP-PBLG. In the process of HAP modification, the morphology changes from rod to sheet and from flake to needle. The effect of BLG-NCA concentration on the character of hydroxyapatite-β-alanine-poly(γ-benzyl-L-glutamate) (HAP-PBLG) was investigated. The existence of amino acids on the HAP surfaces was confirmed in the resulting Fourier transform infrared (FTIR) spectra. The resulting powder X-ray diffraction patterns indicated that the crystallinity of HAP decreased when the ratio of BLG-NCA/HAP-NH2 increased to 20/1. Transmission electron microscopy (TEM) indicated that the particle size of HAP-PBLG decreased significantly and that the resulting particles appeared less agglomerated relative to that of the HAP-NH2 crystals. Furthermore, 1H-NMR spectra and FTIR spectra revealed that hydroxyapatite-β-alanine-poly (L-glutamic acid) (HAP-PLGA) was able to successfully bear carboxylic acid groups on its side chains.
Poly(l-lactide-co-caprolactone) (PLCL) is the polymeric material with good biodegradability and biocompatible properties, but it is insufficient in strength properties that the pure PLCL is performed as orthopedic bandage. The PLCL has been blended with the laponite which is modified by cetyltrimethylammonium bromide (CTAB) to prepare composited bandage splines. The organic-modified laponite (OM-laponite) results of Fourier transform infrared (FTIR) and thermogravimetry analysis (TG) indicate that the laponite was successfully grafted with CTAB and the thermal stability was improved with increasing CTAB. The mechanical properties reveal that elongation at break strengthen with the increasing OM-laponite. When the content of OM-laponite is 2.0 %, the elongation at break and tensile strength of composited spline are superior to the medical orthopedic bandage. The results of thermal stability show that it was helpful to improve the crystallization properties of PLCL with the addition of OM-laponite. The water contact angle results demonstrate that the hydrophilicity is enhanced and is beneficial to cell adhesion. The results of cell experiment illustrate that the composite materials have a certain effect on cell proliferation when the content of OM-laponite is less than 2 %. Compared with the medical orthopedic bandage, it is satisfied with the application requirements.