Hong Bo Liu

Flame Retardant Polyamide 6 Composites Using NMH or NMH/MCA/APP

In this paper, flame retardant Polyamide 6 (PA6) composites were prepared by nano-magnesium hydroxide (NMH) or its composites with melamine cyanurate(MCA) and ammonium polyphosphate(APP). Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to analyze the structure of nano-magnesium hydroxide. The properties including tensile properties, molten index (MFI), rockwell hardness and density of flame retardant PA6 were analyzed. Orthogonal experiments were used to study flame retardancy of PA6 with NMH, MCA and APP. The results showed NMH had hexagonal orthorhombic crystal structure with size of 300×200×100nm. Density of polyamide 6 showed an upward trend when the content of NMH was increasing, the mechanical properties and hardness changed little while processing performance serious declined. The flame retardance of nitrogen-phosphorus -inorganic flame retardants was not desirable.

Preparation and Characterization of C@PSt Microspheres by High Speed Homogenization-Assisted Suspension Polymerization

Spherical C@PSt microspheres with average size around 2 μm were successfully prepared using high-speed homogenization-assisted suspension polymerization of styrene in the presence of carbon black modified by oleic acid. The effects of initiator varieties and initiators concentration on the fractional conversion were investigated. Compared with BPO, AIBN has higher efficiency to initiate the polymerization. LPSA, SEM and OM results showed the prepared microspheres had spherical morphology with the carbon black in the core and PSt in the shell. About 10 weight percentages of carbon black were encapsulated in the complex microspheres proved by TGA results.

The Mechanical Properties of Modified Attapulgite Reinforced Nature Rubber and Styrene-Butadiene Rubber Nanocomposites

Attapulgite (AT)/natural rubber (NR)/ styrene-butadiene rubber (SBR) nanocomposites have been prepared after attapulgite was modified by different coupling agent. The treatment of AT caused the adhesion between AT nanorods and the nature rubber/styrene-butadiene rubber was improved, which enhanced the tensile properties of the matrix. The tensile strength of composites attained 15.6 MPa after AT was modified by 3%wt Si-69 coupling with addition of 20 phr.

Preparation and Charcterisation of PSt/GMA/DVB Microspheres by Soap-Free Emulsion Polymerization

PSt/GMA/DVB microspheres were prepared by soap-free emulsion co-polymerization of St, GMA and DVB monomers. The fractional conversion of polymerizations was characterized by gravimetric methods. All the fractional conversions of polymerization exceeded 90 percentages. The amounts of epoxy groups on the microspheres were measured by hydrochloric acid- acetone method. The results showed that the added time of GMA monomers had little influence on the amounts of epoxy groups in the microspheres; however, with the increasing of GMA monomers, the epoxy groups increased; with the increasing of DVB monomers, the epoxy groups drastically decreased.

Application of a Novel Initiator on Acrylic Emulsion Polymerization

New initiator of FFM6 is used to initiate the acrylic emulsion polymerization. The influences of concentration of FFM6 (c[I]) and polymerization temperature (T) on polymerization reaction rate (Rp) were discussed. Rp is proportional to (c[I])1.4 which is different with classical emulsion polymerization whose Rp is proportion to (c[I])0.4, that indicate polymerization mechanism of the reaction in the study is different with classical mechanism. The value of Ea, 56.4 kJ/mol, is lower than the value of general radical polymerization’s Ea (80.0-96.0 kJ/mol), which indicates the FFM6 can initiate acrylic emulsion polymerization at a lower temperature compared with the other kinds of initiator.

The Application of Calcium Sulfate Whisker in Styrene-Acrylic Emulsions

The styrene-acrylic emulsions were prepared by copolymerization of styrene, acrylic acid and n-butyl acrylate; coatings were achieved by adding calcium sulfate whiskers and titanium dioxides at the presence of dispersing agents and rheological additives. The physical and mechanical properties as well as contact angles of coating films formed on tinplate were characterized in detail. The pencil hardness was slightly decreased; the contact angle was greatly decreased from 69.8o to 12oby adding the calcium sulfate to indicate the hydrophilic coating films may have self-cleaning properties.

Research of Properties and Preparation on Zero-VOC Acrylic Elastic Emulsion

The core-shell acrylic emulsion was synthesized，with P(MMA/BA) as core，and with P(2-EHA/MBA/HPA) as shell. The influence of the mass ratio of core/shell on mechanical properties was investigated in detail. The high elongation at break proved that the emulsion may have a potential application in coating industry, afforded by HPA as functional monomer. However, when the amount of HPA exceeds 1.5 wt. % to the total monomers, the emulsion will become unstable and precipitation occurs.

The Performance of Barium Sulfate/Nature Rubber Composites Using in Sport Shoes

Modified barium sulfate (MBS) /nature rubber(NR) composite materials were prepared by direct blending methods. Barium sulfate was modified by coupling agent Si-69, titanium esters and stearic acid. Tensile property, hardness and wear resistance of composite materials were studied by various methods. The results showed that the modified barium sulfate fillers had great effect on the reinforcement of the composites.