Nano-emulsion of methylmetacrylate / butyl acrylate crosslinked an application in acrylic emulsion paints

This work proposes self-crosslinked nano-emulsion synthesized by emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA), methacrylic acid (MAA) and mixed emulsifier via pre-emulsified and semi-continuous seeded emulsion polymerization technology in the presence of N-methylolacryamide and glycedyl methyl acrylate. Emulsions used as pigment binders have to deal with the challenge to assure an outstanding film configuration and exterior as well as good mechanical properties. The influence of the mass ratio of BA to MMA, the amount of N-methylolacryamide and glycedyl methyl acrylate on the paint's properties of the self-crosslinked emulsion was examined. And the relationship between emulsion viscosity and particle size was investigated. The results show that the self crosslinked acrylate emulsion with high viscosity can be synthesized with 50:50 monomer composition of BA: MMA and added amount of N-methylolacryamide is 0.3%−1.0% and added amount of solidum persulphate is 0.5%−1.5%. The particle size of emulsion in the range of 200 to 470 nm. The self-crosslinkage process of N-methylolacryamide involves two steps. . K E Y W O R D S Self-cross linkage | Acrylate nano-emulsion | Methyl methacrylate | Butyl acrylate | Condensation reaction C I T A T I O N Singh, Jaspal; Chawla, Malvika; Rawat, Kavita; Singh, Om and Kaushik, R. D. (2018): Effect of monocrotophos on small intestine of mice. ESSENCE Int. J. Env. Rehab. Conserv. IX (1): 46—54. https://doi.org/10.31786/09756272.18.9.1.107 https://eoi.citefactor.org/10.11208/essence.18.9.1.107 Original Research Article Nano-emulsion of methylmetacrylate / butyl acrylate crosslinked an application in acrylic emulsion paints Singh, Jaspal; Chawla, Malvika; Rawat, Kavita; Singh, Om and Kaushik, R. D. Department of Chemistry, Gurukul Kangri Vishwavidyalaya, Haridwar, Uttarakhand, India Corresponding Author: sjs2874@yahoo.com International Journal for Environmental Rehabilitation and Conservation ISSN: 0975 — 6272 IX (1): 46— 54 www.essence-journal.com A R T I C L E I N F O Received: 10 February 2018 | Accepted: 22 April 2018 | Published Online: 15 August 2018 DOI: 10.31786/09756272.18.9.1.107 EOI: 10.11208/essence.18.9.1.107 Article is an Open Access Publication. This work is licensed under Attribution-Non Commercial 4.0 International (https://creativecommons.org/licenses/by/4.0/) ©The Authors (2018). Publishing Rights @ MANU—ICMANU & ESSENCE—IJERC. ESSENCE—IJERC | Jaspal et al. (2018) | IX (1): 46—54 47 Introduction The process of emulsion polymerization consists of dispersing a uniform emulsion in an aqueous phase with the aid of surfactants. Emulsion polymerization can also be defined as an addition polymerization process which proceeds by micellar mechanism. The polymer formed is stabilized within the emulsion by absorption onto surfactants as the polymerization proceeds. This gives polymers with high molecular weight, greater flexibility, good reproducibility, rapid reactions, high monomer conversion and low cost relative to other polymerization techniques. Compared to other heterogeneous polymerization, like suspension or precipitation, it is likely the most complicated system; all this factor make modeling of this system very difficult (Aggarwal et. al., 2007; Alexander and Napper, 1971). Acrylate emulsions manufactured by this technique are widely used in preparing emulsion paints. Acrylate emulsions are widely used owing to their good water resistance, weather resistance, ageing resistance and flexibility at low temperature (Antonietti and Landfester, 2002). They have excellent durability, which makes them suitable for indoor and outdoor decorative paints, and can be formulated into highresistance coatings for industrial uses. Selfcrosslinked acrylate emulsions can be prepared via molecular design when some functional groups are introduced into the molecular chain of a polymer (Aslamazova, 1995; Asua, 2002; Barrett, 1975). Many studies have been carried out to analyze the effect of the nature and type of the emulsifier in emulsion polymerization. Emelie et al (Bockhorn, 1992) studied the batch emulsion copolymerization of methyl methacrylate and butyl acrylate using anionic (Sodium lauryl sulfate) and nonionic (polyethylene oxide ether) surfactants and other studied the stabilization (Candau, 1992) effect of mixed surfactant effect system in the batch polymerization of styrene, work was later continued by Chu and coworkers using methyl methacrylate and bytyl acrylate. Gan et al., (1993) and Candau, (1999) have carried out extensive work on micro emulsion polymerization of methyl methacrylate and other acrylate monomers, using various types of surfactant. Representative review or journal articles concerning emulsion polymerization can be found in references (Capek, 1999; Capek, 1999a; Capek, 1999b; Capek, 2001; Capek, 2002; Capek and Chern, 2001; Chern, 2002; Chern, 2003; Chu and Lin, 1992; Cunningham, 2002; El-Aasser and Miller, 1997; Emelie et. al., 1985; Gan et. al., 1993; Gao and Penlidis, 2002; Guyot, 1999; Kawaguchi, 2000; Leonardi et. al., 2005; Li and Brooks, 1992; Li-jun et. al., 2008; Moriguchi et al., 1999; Nagai, 1996; Nomura and Tobita, 2005; Poehlein and Dougherty, 1977; Snuparek, 1996; Sudol and El-Aasser, 1997; Tian-ying et. al., 2005; Tianying et. al., 2006; Ugelstad and Hansen, 1976). In this work, self-crosslinked acrylate emulsion with high elasticity was prepared via pre-emulsified and semi-continuous seeded emulsion polymerization technology by using N hydroxyl methyl acrylamide as self-crosslinked monomer and poly solidum maleate as protective colloid. Possible cross-linked mechanism of self-crosslinked monomer was put forward. In addition, the rheological properties of the prepared acrylate emulsion were analyzed (Vanderhoff, 1985; Wang et. al., 1994; Yan-jun et. al., 2003). Experimental Raw materials Butyl acrylate (BA), methyl methacrylate (MMA) and methacrylic acid (MAA) were distilled under reduced pressure to remove the polymerization inhibitor before use. Potassium persulfate (KPS, Sigma-Aldrich) was recrystallized from water. Sodium dodecyl sulfate (SDS, Fisher), Nmethylol acrylamide (NMA, Sigma-Aldrich), hexadecane (HD, Sigma-Aldrich, 99%), and NaHCO3 (E.Merk), ammonia water (E.Merk), methacrylic acid (Sigma-Aldrich), Nhydroxymethyl acrylamide (Sigma-Aldrich), poly sodium maleate were used. All the chemicals and reagents used were of analytical grade. Deionized water was used for preparation of the solutions. grade. Deionized water was used for preparation of the solutions. ESSENCE—IJERC | Jaspal et al. (2018) | IX (1): 46—54 48 Method Pre-Emulsification: The pre-emulsification having two components, one was a solution of the surfactant system in water and the second was a mixture of monomers in the required ratio (like 45:55:: 50:50:: 55:45:: 60:40 of MMA & BA respectively for 50±1 solid content) and special monomer (like AA, NMA, GMA). The solution of the surfactant system contains anionic and non-ionic surfactant. The mixture of monomers was dispersed into the solution of surfactant with high speed stirring. Semi Continuous Emulsion Polymerization: The semi continuous emulsion polymerization was carried out in a glass reactor. The surfactant solution containing ~33% anionic surfactant, buffer and other additives as required was charged into the reactor, the whole system was set up and heated to 80-85oC. The initiator dissolved in a desired quantity of de-ionized water was added just before the seed; then 40g of pre-emulsion was added in reactor as a seed. After 15 min of seeding, the feed flow was started. The feed containing preemulsion was added over 150 min at 80 ± 2°C temperature. The polymerization was continued thereafter in batch for about 1 hour, to kill unreacted monomer. After 1 hr. the reactor cooled down to 35 °C and ammonia was added drop wise for adjustment to pH (8-9). The emulsion was discharged from glass reactor and filtered through 200 mesh. Characterization The emulsion prepared was characterized for their ability to perform as a binder in paints. 1. Solid Content (% NVM): This method is used to determine the percentage of non-voaltile material. The weighed quantity of sample was wrapped in aluminium foil and then kept in oven at 105 °C for 3 hours. The amount of solid content was determined by using following formula: %NVM = (W3 – W1)/ (W2 – W1) X 100 Where, W1 = Weight of empty aluminium foil W2 = Weight of aluminium foil with sample W3 = Weight after drying sample 2. pH at 300 °C: A digital pH meter standardized against buffer solution was employed. 3. Viscosity (poise): The viscosity of the emulsion was tested by Brookfield viscometer at 300 °C. Then calculated by given formula: Viscosity = (Recorded X Tablulated ) ÷ 100 4. Particle size (nm): The droplet sizes of unpolymerized microemulsions and the particle sizes of polymerized latexes were determined with a transmission electron microscope. 5. Freeze-thaw stability (cycle): The exact test condition may be varied to suit the condition expected to be encounted in actual use. A typical cycle involves freezing at -15 °C for 16 hours, followed by thawing at ambient temperature. This cycle was repeated as often as required. 6. Electrolytic stability: The electrolytic stability was tested by using 10% solution of CaCl2. The equal volume of the emulsion and solution of CaCl2 was kept at room temperature for 72 hours. 7. Minimum film forming temperature: Minimum Film Forming Temperature (MFFT) is the lowest temperature at which an emulsion will uniformly coalesce when laid on a substrate as a thin film. Continuous films are obtained at a temperature near the glass transition temperature of the polymer or more precisely, above the MFFT. 8. Hardness: Hardness is defined as a resistance of a material to deformation, indentation or scratching. The test was performed using Rock well hardness. A specimen was kept on a hard, flat surface and an average of