Synthesis of polymerizable quaternary ammonium emulsifier and properties of its fiber crosslining emulsion

Synthesis of Castor Oil-Based Quaternary Ammonium Salt and Modification of Attapulgite for Treating Industrial Wastewaters

In order to develop multifunctional quaternary ammonium salts and explore their advantages as modifiers for wastewater treatment, castor oil-based quaternary ammonium salts were synthesised and subsequently used as modifiers for attapulgite treatment. The structures of untreated and treated attapulgite were compared by Fourier transform infrared spectra and X-ray diffraction. The mechanism of modification was speculated. Various factors such as the amount of modified attapulgite, temperature and pH were also investigated in the batch experiments on the removal rates of acetone and phenol from wastewaters. The synthesis conditions were set as follows: the reaction temperature was 80 °C, the reaction time was 8 h, the molar ratio of castor oil to N,N-dimethyl-1,3-propanediamine was 1:5, the catalyst was 6% NaOH and the product yield was about 64.72%. The grafting rate of the castor oil-based quaternary ammonium salt was about 99.6% when the amount of modifier was 0.69 g per 5 g of attapulgite, the ultrasound treatment time was 11 min and the pH was 5. The quaternary ammonium salt was only associated with the surface of attapulgite and did not change the rod-like crystal structure of the silicate. The modified attapulgite is much more fibrous and exhibits a good distribution of crystal bundles. The removal rates were found to be less favourable under strongly acidic and strongly alkaline conditions. Under suitable conditions, for 50 mL industrial wastewaters (phenol: 100-160 mg/L; acetone: 680-800 mg/L), the amount of modified attapulgite was 1 g, the temperature was 80 °C and the pH was 7, and the maximum removal rates of acetone and phenol after 80 min reached about 65.71% and 78.72%, respectively, which were higher than those of ATP.

Synthesis of a castor oil-based quaternary ammonium surfactant and its application in the modification of attapulgite

Castor oil-based quaternary ammonium surfactant (COQA) was synthesized by an ester-exchange reaction of refined castor oil (CO) (raw material) with N,N-dimethyl ethanol amine followed by quaternization with epichlorohydrin (ECH). Its surface activity and structural features were determined. The critical micelle concentration (CMC) of the surfactant at 25 °C was 1.79 × 10−3 mol/L. The surface tension of an aqueous COQA solution at CMC was 38.19 mN/m. Subsequently, the synthesized COQA was used to modify attapulgite (ATP) by binding it to the surface of ATP. The change in the morphology of the modified-ATP (M-ATP) was attributed to the presence of the COQA bound to the surface of the rod-shaped crystals, although the crystal structure of the silicate did not change. Compared to ATP, the microstructure of the M-ATP was less rigid.

Preparation and Evaluation of Antimicrobial Hyperbranched Emulsifiers for Waterborne Coatings

Nosocomial infections are a major problem in medical health care. To solve this problem, a series of antimicrobial waterborne paints were prepared by using antimicrobial hyperbranched (HB) emulsifiers. The HB-emulsifiers were prepared by polymerizing AB₂ monomers obtained in a one-step reaction of bis(hexamethylene)triamine and carbonyl biscaprolactam. The blocked isocyanate end groups (B groups) of the HB-polymer were utilized to introduce tertiary amino groups through the reaction with compounds comprising either a hydroxyl or a primary amino group and a tertiary amino group. Quaternization of the tertiary amines with 6 different alkyl bromides resulted in 12 amphiphilic cationic species. The 12 emulsifiers showed the successful inhibition and killing of 8 bacterial and 2 fungal strains. The killing efficacy increased with increasing alkyl chain length. The octyl-functionalized compound was chosen for suspension polymerizations because of the good compromise between killing and emulsifying properties. With this emulsifier, aqueous poly(methacrylate) suspensions were prepared, which were stable and had excellent killing properties.

Engineered Multifunctional Fluorinated Film Based on Semicontinuous Emulsion Polymerization Using Polymerizable Quaternary Ammonium Emulsifiers

Along with society’s progress, high-quality coatings are widely used. Although fluorinated polymers were successfully prepared by semicontinuous emulsion polymerization with surfactants, chlorotrifluoroethylene (CTFE), and acrylate monomers, the optimization collocation of surfactants still has room for improvement. The traditional emulsifiers are physically absorbed onto the surface of latex particles. The latex film generated by latex particles is unstable in water, which limits its application. Herein, a novel series of cationic quaternary ammonium polymerizable surfactant was selected because it can react with CTFE and acrylate monomers and can become a part of the polymers. We also studied the effects of emulsifier type on resultant emulsion properties. In addition, wonderful weatherability, water resistance, and antibacterial and antifouling of the multifunctional fluorinated films were observed, which would open up a bright future for coating industries.

Aggregation behaviours and bactericidal activities of novel cationic surfactants functionalized with amides and ether groups

Novel cationic surfactants exhibit high surface activity, interesting aggregation behaviors in aqueous solution and excellent bacterial activity.