Polylactide (PLA)/halloysite nanotube (HNT) nanocomposites with different HNT contents were prepared by melt compounding. The morphology, crystallization behavior, as well as thermal and mechanical properties of the nanocomposites were studied. The results showed that HNT were well dispersed in PLA matrix. Thermogravimetric analysis data revealed that the thermal stability of PLA was decreased with the increasing of HNT content. Differential scanning calorimetry analysis indicated that the presence of HNT could promote cold crystallization and lead to different crystalline phase formation. The flexural and tensile modulus of PLA/HNT nanocomposites improved significantly with the incorporation of HNT. Compared with neat PLA foam, PLA/HNT nanocomposite foams showed much higher cell density and smaller cell size due to HNT serving as the heterogeneous nucleating agents. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

We previously proposed a new strategy to fabricate a novel foldable capsular vitreous body (FCVB) as a vitreous substitute and found that the FCVB was a very good replacement for closely mimicking the morphology and restoring the physiologic function of the rabbit vitreous body. The aim of this article was to assess the mechanical, optical, and biocompatible properties of a FCVB made from liquid silicone rubber. The mechanical properties show that the shore hardness is 37.80 degrees, the tear strength is 47.14 N/mm, the tensile strength is more than 7.28 MPa, and the elongation ratio is more than 1200%; in addition, the FCVB has 300 nm mili apertures in the capsule. The optical properties reveal that transmittances are 92%, hazes are 5.74%, and spectral transmittance is 97%. The transmittance mission is 2.3% and can sustain a 1500 mW, 0.2 s, 532 nm green laser. The biocompatible properties are shown in the stable extracts experiment, no significant fever, good genetic safety, and no structural abnormality or apoptosis in the cornea, ciliary body, and retina over a 6-month observation period. These results indicate that the FCVB has good mechanical, optical, and biocompatible properties, and the assessment results can be recommended as the FCVB technical standards for industrial manufacturing and inspection.

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Free-radical reactions of polymers, including biodegradable polymers via reactive extrusion, are normally induced by peroxide chemicals, which are known to lead to the formation of secondary products and impart some performances to the resin. Here, we report an ultraviolet (UV)-induced reactive extrusion, without employing a peroxide initiator, to control chain scission and branching reactions of polylactide (PLA). Through this technique, chain scission reaction of molten PLA induced by UV irradiation during extrusion was promoted to high-level efficiency. Degraded PLA samples had lower complex viscosity and storage modulus, because of random main chain scissions. Long-chain branched (LCB) structure of PLA was obtained when a multifunctional chemical agent, trimethylolpropane triacrylate (TMPTA), was added into the PLA matrix during extrusion. Various rheological plots including viscosity, storage modulus, loss tangent, and Cole–Cole plots were used to distinguish the LCB structures of PLA samples. Thermal and crystallization properties of degraded and branched PLA samples were also investigated by means of differential scanning calorimetry (DSC) and polarized optical microscopy (POM). For the LCB PLA samples, a distinct crystallization exothermic peak appeared and accompanied by the disappearance of the cold crystallization temperature, demonstrating significantly enhanced crystallization rates. This UV-induced reactive extrusion has nonresidues of peroxide, is highly efficient and easily adjustable, and opens new avenues in potential applications for PLA modification, such as grafting and polymerization.