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In situ fibre‐reinforced composite films of poly(lactic acid)/low‐density polyethylene blends: effects of composition on morphology,transport and mechanical properties 下载免费PDF全文
This study aimed to investigate the effects of blend composition on packaging‐related properties of poly(lactic acid) (PLA) and low density polyethylene (LDPE) blown films. Blend films with PLA contents of 5–20 wt% were produced and compared. Scanning electron micrographs of cross‐sectional cryofractured surfaces of the blend films revealed that in situ fibre‐reinforced composites were obtained. Viscosity ratio of the polymer components of ca 1 confirmed that fibre formation was favourable for this blend system. PLA microdomains were dispersed throughout the film in forms of long fibres (length‐to‐diameter ratio > 100) and ribbons. The number of fibres and ribbons increased with an increase of PLA content. Critical content of PLA was found to be 20 wt% for effective improvement of both moduli and gas barrier properties. Incorporation of poly[ethylene‐co‐(methyl acrylate)] compatibilizer showed minimal effect on PLA structure. However, it did improve moduli and O2 barrier properties when sufficient amount (1.5 pph) was used in 10 wt% PLA/LDPE. In short, flow behaviour, ratio of polymer components and degree of compatibility together played intricate roles in the morphology and hence mechanical and transport properties of PLA/LDPE immiscible blends. © 2017 Society of Chemical Industry 相似文献
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Sompong Sansenya Apirak Payaka Wachirawit Wannasut Yanling Hua Saowapa Chumanee 《International Journal of Food Science & Technology》2021,56(4):1865-1876
Rice is produced for consumption and traditional medicine. Rice is also used as an ingredient in cosmetic products. In this study, the author investigated the biological activity and inhibition potential against α-glucosidase, α-amylase and tyrosinase activity of rice extract (black rice [BR], red rice [RR] and white rice [WR]), rice volatile compounds, rice extract combined with volatile compounds, rice extract combined with standard inhibitors and volatile compounds combined with standard inhibitors. The results revealed that the free-radical scavenging capacity of rice extract is related to the phenolic content and flavonoids. BR showed the highest potential to inhibit α-glucosidase and α-amylase activity, whereas WR showed the highest potential to inhibit tyrosinase activity. Among rice volatile compounds, vanillin and vanillyl alcohol had the highest inhibition potential against α-glucosidase and α-amylase, respectively, whereas guaiacol had the highest inhibitory activity against tyrosinase. Molecular docking supported by the high binding efficiency was also obtained from vanillin and guaiacol when located at the active site of these enzymes. The combination of RR with acarbose (AB) had the highest inhibition potential and showed a synergic effect on both α-glucosidase and α-amylase. Interestingly, the combination of rice extract (BR, RR and WR) and vanillin and vanillyl alcohol had a synergic effect on α-amylase. Moreover, the combination of WR and vanillyl alcohol had the highest inhibition potential and showed a synergic effect on tyrosinase, whereas rice volatile compounds had a synergic effect on tyrosinase obtained from 2-pentylfuran/kojic acid (KA), vanillin/KA and vanillyl alcohol/KA. 相似文献
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Saowapa Chotisuwan Jatuporn Wittayakun Rodrigo J. Lobo-Lapidus Bruce C. Gates 《Catalysis Letters》2007,115(3-4):99-107
Bimetallic MgO-supported catalysts were prepared by adsorption of Pt3Ru6(CO)21(μ3-H)(μ-H)3 on porous MgO. Characterization of the supported clusters by infrared (IR) spectroscopy showed that the adsorbed species
were still in the form of metal carbonyls. The supported clusters were decarbonylated by treatment in flowing helium at 300 °C,
as shown by IR and extended X-ray absorption fine structure (EXAFS) data, and the resulting supported PtRu clusters were shown
by EXAFS spectroscopy to have metal frames that retained Pt–Ru bonds but were slightly restructured relative to those of the
precursor; the average cluster size was almost unchanged as a result of the decarbonylation. These are among the smallest
reported bimetallic clusters of group-8 metals. The decarbonylated sample catalyzed ethylene hydrogenation with an activity
similar to that reported previously for γ-Al2O3-supported clusters prepared in nearly the same way and having nearly the same structure. Both samples were also active for
n-butane hydrogenolysis, with the MgO-supported catalyst being more active than the γ-Al2O3-supported catalyst. 相似文献
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Preparation of bioactive glycosylated glial cell‐line derived neurotrophic factor‐loaded microspheres for medical applications 下载免费PDF全文
Poly (lactic‐co‐glycolic acid) (PLGA)‐coated gelatin microspheres containing glial cell‐line derived neurotrophic factor (GDNF) were developed by thermal gelation through a water‐in‐oil emulsion technique. Gelatin types (A and B) at four different pH levels were investigated for their influences on the morphology, the microsphere size, the zeta potential, and the swelling ability. The encapsulation of GDNF and the release characteristics of GDNF were also determined using enzyme‐linked immunosorbent assay (ELISA). The maximum cumulative released amounts of GDNF from the microspheres were increased from 50 to 90% after 4 d (based on the actual amount of the GDNF). Thus, the release of the GDNF contents in the microspheres depends on the amount of GDNF. Trigeminal ganglion cells (TGCs) were used to study the bioactivity of GDNF released from the microspheres, which was proven to retain its bioactivity in promoting the TGCs' neurite outgrowth. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40167. 相似文献
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