Redox initiation in semicontinuous polymerization to search for specific mechanical properties of copolymers

In this work, for a semicontinuous emulsion polymerization reaction, it is shown that using a redox initiation system at 40°C, substantial modifications in copolymer chain composition with conversion can be easily obtained. To test controllable trajectories for comonomer feeding, linear and parabolic profiles were chosen to get different types of chain composition variations for the 50/50 w/w styrene/n-butyl acrylate system. For the “forced composition copolymers,” the molecular weight averages and distribution were obtained by size exclusion chromatography. The composition along conversion was followed by proton nuclear magnetic resonance to determine the weight composition distribution (WCD) of the copolymer chains. Mechanodynamic (dynamic-mechanical analysis), tensile, and hardness tests exhibited consistent results depending on the WCD that outcomes from the respective feeding profile. The results confirm that this methodology is of great potential for industrial applications when looking for synergy in copolymer properties, and low-cost processes.

Bioactive hydrogel coatings of complex substrates using diffusion-mediated redox initiation

Iron diffusion-mediated hydrogel crosslinking is a facile method to generate conformable hydrogel coatings with tunable thickness, multilayer structures, and bioactivity.

Self-assembly of nanoencapsulated undecanoic acid on cotton fiber for thermoregulating textiles

We herein report the preparation of phase change nanocapsules with undecanoic acid (UA) as the core and a styrene–butyl acrylate copolymer as the shell by miniemulsion polymerization using interfacial redox initiation.

Enhancing the self-recovery and mechanical property of hydrogels by macromolecular microspheres with thermal and redox initiation systems

A redox initiation system was used to efficiently enhance the mechanical behavior of macromolecular microsphere hydrogels.

Synthesis of High Performance Polycarboxylate Superplasticizer through Redox Initiation System and its Application in Concrete

A high performance polycarboxylate superplasticizer (PCE) was successfully synthesized by a polymerization reaction among acrylic acid (AA), maleic anhydride (MA) and isopentenyl polyethylene glycol (IPEG) through redox initiation system. The composition and amounts of initiation system, and the ratio of monomers were investigated respectively. The proportion of IPGE: MA: AA: sodium methallyl sulfonate (SMAS): ammonium persulfate (APS): ascorbic acid (ASA) was determined as 1: 3: 1.5: 0.3: 0.015: 0.012. Moreover, the effect of polymerization temperature on PCE’s cement paste fluidity was studied. The results showed that the cement pastes mixed with PCE synthesized at 10°C, 20°C and 30°C respectively exhibited better fluidity performances than that mixed with common PCE. The Fourier Transform Infrared Spectroscopy (FTIR) measurements were used for the structural characterization. The results confirmed the occurrence of polymerization reaction and the ideal structure. Furthermore, the application performances of PCE synthesized through redox initiation system in mortar and concrete were tested. The results showed that the water reducing rate of PCE in mortar and the slump performances of PCE in concrete were better than those of the common commercial PCEs. This synthesis method presents the great research value and application prospect for the PCE preparation in concrete engineering.