Preparation and characterization of biodegradable aliphatic-aromatic copolyesters/nano-SiO_2 hybrids via in situ melt polycondensation

In situ melt polycondensation was proposed to prepare biodegradable aliphatic-aromatic copolyesters/nano-SiO2 hybrids based on terephthalic acid （TPA）, poly（L-lactic acid） oligomer （OLLA）, 1,4-butanediol （BDO） and nano-SiO2. TEM and FT-IR characterizations confirmed that TPA, OLLA and BDO copolymerized to obtain biodegradable copolyesters, poly（butylene terepbthalate-co-lactate） （PBTL）, and the abundant hydroxyl groups on the surface of nano-SiO2 provided potential sites for in situ grafting with the simultaneous resulted PBTL. The nano-SiO2 particles were chemically wrapped with PBTL to form PBTL/nano- SiO2 hybrids. Due to the good dispersion and interfacial adhesion of nano-SiO2 particles with the copolyester matrix, the tensile strength and the Young＇s modulus increased from 5.4 and 5.6 MPa for neat PBTL to 16 and 390 MPa for PBTL/nano-SiO2 hybrids with 5 wt.% nano-SiO2, respectively. The mechanical properties of PBTL/nano-SiO2 hybrids were substantially improved.

Synthesis and hydrosilation of multi-vinyl branched siloxane for self-healing system

In this work, the preparation of α,ω-dichloride-terminated multi-vinyl branched siloxane 1 （yield： 57.1%） used for self-healing polymer composites were synthesized via ring-opening of 1,3,5,7-tetravinyl-1,3,5,7-tetramethyl-cyclotetrasiloxane （D4^vi） in the presence of vinylmethydichlorosilane （VM-32）. 1 was hydrogenated by aluminum lithium hydride （LiAlH4） to get self-healing monomer 2 （yield： 79.8%） which contained both Si-H bonds and Si-vinyl bonds. Then hydrosilation occurred between these two bands and finally silicone 3 was obtained, showing the potential of self-healing.

Synthesis of Methyl-(γ-chloropropyl)dichlorosilane Catalyzed by Silica-supported Karstedt-type Catalyst

Methyl-（γ-chloropropyl）dichlorosilane was synthesized under the catalysis of a silicasupported Karstedt-type catalyst. By orthogonal experimental design method, the optimum reaction parameters such as reactants ratio, reaction temperature and time, and the dosage of catalyst, were determined. At the optimum reaction condition the product yield reached 78.42%, which is higher than that reported in the literatures.

Functionalization of polyhedral oligomeric silsesquioxanes with bis(hydroxyethyl) ester and preparation of the corresponding degradable nanohybrids

One novel difunctionalized polyhedral oligomeric silsesquioxanes （POSS） derivative was designed and synthesized by a convenient method with high yield. 1H NMR and P＇r-IR characterizations suggested that Michael addition reaction successfully took place between 2-hydroxyethyl acrylate （HEA） and aminopropylisobutyl POSS （POSS-NH2） under mild conditions, which finally formed bi（hydroxyethyl） ester-functionalized POSS derivatives （BH-POSS）. Due to the similar functional groups and high reactivity, BH-POSS could be easily incorporated into the main-chain of biodegradable aliphatic-aromatic copolyesters PBTL via in situ melt polycondensation to prepare corresponding degradable nanohybrids with high mechanical properties.