Chitosan-hybridized acrylic resins prepared in emulsion polymerizations and their application as interior finishing coatings.Chitosan was used to introduce formaldehyde adsorption adsorption, adhesion of the molecules of liquids, gases, and dissolved substances to the surfaces of solids, as opposed to absorption, in which the molecules actually enter the absorbing medium (see adhesion and cohesion). abilities into an emulsion binder for interior finishing coatings. Chitosan-hybridized acrylic emulsions were prepared by two methods. To produce stable chitosan-hybridized acrylic emulsions, the pre-emulsion dropping method is superior to the monomer monomer (mŏn`əmər): see polymer. monomer Molecule of any of a class of mostly organic compounds that can react with other molecules of the same or other compounds to form very large molecules (polymers). dropping method. The adsorption performances for formaldehyde in chitosan-hybridized acrylic resin films increased with increasing chitosan contents; the films also had adsorption abilities for hydrogen sulfide hydrogen sulfide, chemical compound, H2S, a colorless, extremely poisonous gas that has a very disagreeable odor, much like that of rotten eggs. It is slightly soluble in water and is soluble in carbon disulfide. and ammonia. Tensile strengths and elongation at breaking points decreased with increasing chitosan contents. Interior finishing coatings made from chitosan-hybridized acrylic resin emulsions have the qualities necessary for an interior finishing coating and showed excellent adsorption abilities for formaldehyde. Keywords: Acrylics, latexes, colloids, emulsions, waterborne, mechanical properties, architectural, water-based, air quality, emissions, VOC (Vertical Online Community) See vertical portal. control ********** In the living environment, sick-building syndrome is a social health problem which occurs when the quality of indoor air diminishes due to harmful substances contained in it. (1) Volatile organic compounds volatile organic compound Environment Any toxic cabon-based (organic) substance that easily become vapors or gases–eg, solvents–paint thinners, lacquer thinner, degreasers, dry cleaning fluids (VOCs) such as formaldehyde cause sick-building syndrome because VOCs are contained in furniture and building materials Building materials used in the construction industry to create . These categories of materials and products are used by and construction project managers to specify the materials and methods used for . . (2) To combat this problem, a considerable number of studies have been done to improve indoor air quality Indoor Air Quality (IAQ) deals with the content of interior air that could affect health and comfort of building occupants. The IAQ may be compromised by microbial contaminants (mold, bacteria), chemicals (such as carbon monoxide, radon), allergens, or any mass or energy stressor . (3,4) In interior materials, both the decomposition of formaldehyde using photocatalysts such as titanium oxide, and decomposition using chemical means or the physical adsorption of formaldehyde, have been studied. (5-10) Although the means for decomposing formaldehyde are effective, if sufficient ultraviolet radiation cannot be supplied throughout the indoor environment, undecomposed formaldehyde remains. In the case of physical adsorption with porous raw materials such as zeolite zeolite Any member of a family of hydrated aluminosilicate minerals that have a framework structure enclosing interconnected cavities occupied by large metal cations (positively charged ions)—generally sodium, potassium, magnesium, calcium, and barium—and water , diatomite, and charcoal, there is a problem in that adsorbed formaldehyde is emitted. On the other hand, chemical adsorption by reactions with formaldehyde can be efficiently removed and not re-emitted. Chemical adsorbents, however, are not sufficiently safe. Recently, investigations using natural raw materials as adsorbents were carried out. Among the natural raw materials, chitosan is an environmentally friendly Environmentally friendly, also referred to as nature friendly, is a term used to refer to goods and services considered to inflict minimal harm on the environment.[1] material with many superior properties. Chitosan powder was used to inhibit the emission of formaldehyde from plywood. (11-12) Ishimaru also reported that chitosan is effective in adsorbing formaldehyde. (13) Chitosan is a polysaccharide polysaccharide: see carbohydrate. polysaccharide Any of a large class of long-chain sugars composed of monosaccharides. Because the chains may be unbranched or branched and the monosaccharides may be of one, two, or occasionally more kinds, consisting of 2-amino-2-deoxy-D-glucopyranose as a repeating unit and is obtained by deacetylation of chitin, as shown in Figure 1. Chitin exists in crustacean crustacean (krŭstā`shən), primarily aquatic arthropod of the subphylum Crustacea. Most of the 44,000 crustacean species are marine, but there are many freshwater forms. shells, such as crabs and shrimps; in insects, such as beetles and grasshoppers Grasshoppers may refer to one of the following:
the quality of not having toxic or injurious effects on biological systems. biocompatibility 1. The extent to which a foreign, usually implanted, material elicits an immune or other response in a recipient 2. , biodegradability, and no toxicity. In addition, chitosan has reactive amino groups on pyranose rings and becomes a cationic cationic having qualities dependent on having free cations available. cationic detergents are wetting agents that disrupt or damage cell membranes, denature proteins and inactivate enzymes. polymer upon the protonation protonation (prō`tənā'shən), in chemistry, addition of a proton to an atom, molecule, or ion. The proton is the nucleus of the hydrogen atom; the positive hydrogen ion, H+, consists of a single proton. of its amino groups. However, chitosan simply added to waterborne coatings cannot uniformly disperse. Furthermore, when chitosan-acid solution is added to waterborne coatings using acrylic emulsions, precipitates are formed because chitosan is a cationic polymer. To resolve this problem, chitosan-hybridized acrylic resins were investigated in emulsion polymerizations between chitosan-acrylic acid ion complexes and acrylic monomers. In this study, the preparation of chitosan-hybridized acrylic resins in emulsion polymerization and their application to interior finishing coatings are discussed. [FIGURE 1 OMITTED] EXPERIMENTAL Materials Chitosan (Kyowa Tecnos Co., Ltd., Japan C-60M) used in this study was deacetylated at 88.2%. Acrylic acid acrylic acid /acryl·ic ac·id/ a readily polymerizing liquid used as a monomer for acrylic polymers. (AA), methylmethacrylate (MMA (Microcomputer Managers Association, Inc.) A membership organization with chapters throughout the U.S. that was devoted to educating personnel responsible for personal computers. It disbanded in 1996. Mma - A fast Mathematica-like system, in Allegro CL by R. Fateman, 1991. ), 2-ethylhexylacrylate (2EHA EHA European Hematology Association EHA Economic History Association EHA Emmanuel Hospital Association EHA Education for All Handicapped Children Act of 1975 EHA Empty Homes Agency EHA English Hockey Association EHA Electrohydrostatic Actuator ) monomers, and the 2,2-azobis(2-aminopropane) dihydrochloride (ABAP ABAP Advanced Business Application Programming ABAP Anheuser-Busch Adventure Parks ABAP As Baller As Possible ABAP Abbreviated Ssi Application Process ) initiator were of reagent grade from Wako Pure Chemical Industries, Japan. Adeka Reasoap NE-20 and NE-30, which are reaction products of polyalkylene glycol glycol (glī`kōl), dihydric alcohol in which the two hydroxyl groups are bonded to different carbon atoms; the general formula for a glycol is (CH2)n(OH)2. alkyl alkyl /al·kyl/ (al´k'l) the monovalent radical formed when an aliphatic hydrocarbon loses one hydrogen atom. al·kyl n. ether with allyl allyl /al·lyl/ (al´il) a univalent radical, —CH2dbondCHCH2. al·lyl n. The univalent, unsaturated organic radical C3H5. glycidyl ether, used as reactively emulsifying nonionic surfactants, were obtained from Asahi Denka Co., Ltd., Japan. The numbers 20 and 30 in NE-20 and NE-30 are the contents of ethylene oxide ethylene oxide Occupational medicine A gas used to sterilize medical supplies and other materials component, respectively. An aqueous solution of 38% reagent grade formaldehyde was purchased from Wako Pure Chemical Industries. An aqueous solution of 28% reagent grade ammonia was also purchased from Wako Pure Chemical Industries. Hydrogen sulfide used in this study consisted of a balanced gas of 1.0 vol% hydrogen sulfide/nitrogen balance gas and was purchased from Nippon Sanso Co., Ltd., Japan. [FIGURE 2 OMITTED] [FIGURE 3 OMITTED] Emulsion Polymerization Traditionally, most emulsion polymers used in architectural coatings have required the use of coalescing coalescing (kō  les´ing),n a joining or fusing of parts. agents to optimize film properties. When the inside of an emulsion particle is homogeneous in composition, the minimum film-forming temperature (MFT (1) (Master File Table) A list of files in an NTFS volume. It contains the name, size, time and date, etc. for each file. See NTFS and FAT. (2) (Managed File T ) is mostly conformable to a glass transition temperature The glass transition temperature is the temperature below which the physical properties of amorphous materials vary in a manner similar to those of a solid phase (glassy state), and above which amorphous materials behave like liquids (rubbery state). in an emulsion. In order to form a film at lower temperatures, it is wellknown that the MFT is predicted from the theoretical glass transition temperature. (14) The purpose of this study is the development of interior finishing coatings without coalescing agents. Therefore, the theoretical glass transition temperature from monomers composed of chitosan-hybridized acrylic resins is below 0[degrees]C. Table 1 shows the components of emulsion polymerization. If all the AA, MMA, and 2EHA monomers are polymerized and there are no unreacted monomers, the content of chitosan in this emulsion would be about 4 wt% in solid. Chitosan-hybridized acrylic emulsion polymerizations were carried out by the following two methods: monomer dropping and pre-emulsion dropping. Figure 2 shows the processes for (a) the monomer dropping method and (b) the pre-emulsion dropping method, respectively. In the monomer dropping method system, (15-17) 10.9 g of chitosan were added to 4.4 g AA to prepare a chitosan solution. In this solution, chitosan was dissolved as a chitosan-AA salt, as shown in Figure 3. Then, 88.4 g MMA and 179.2 g 2EHA were mixed into the chitosan solution to prepare a monomer mixture. First, 10% of the monomer mixture was added and stirred at 500 rpm with an aqueous solution consisting of 14.3 g NE-20, 4.2 g NE-30, and 540 g ion exchanged water in a separate one-liter flask equipped with a thermometer, a dropping funnel A dropping funnel is a type of laboratory glassware used to transfer fluids. They are fitted with a stopcock which allows the flow of to be controlled. Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. , and a condenser condenser Device for reducing a gas or vapour to a liquid. Condensers are used in power plants to condense exhaust steam from turbines and in refrigeration plants to condense refrigerant vapours, such as ammonia and Freons. . Both the remaining 90% of the monomer mixture and 0.8 g of the initiator ABAP were continuously dropped and stirred at 60[degrees]C for two hours. After two hours, the initiator 0.2 g ABAP was added and the reaction mixture was kept at 70[degrees]C for two hours. The pre-emulsion polymerization polymerization Any process in which monomers combine chemically to produce a polymer. The monomer molecules—which in the polymer usually number from at least 100 to many thousands—may or may not all be the same. system (15-17) was performed in stages. In the first stage, 10.9 g of chitosan were added to 4.4 g AA to prepare a chitosan solution. Next, 88.4 g MMA, 179.2 g 2EHA, the chitosan solution, 1.7 g NE-20, and 240 g ion exchanged water were emulsified at 10,000 rpm using a homogenizer A laboratory equipment for the homogenization of various types of material, such as tissue, plant, food, soil, and many others. Many different models have been developed using various physical technologies for the disruption. . In the second stage, the emulsified mixture and 0.8 g of the initiator ABAP were continuously dropped into an aqueous solution of nonionic surfactants, which was a mixture of 12.6 g NE-20, 4.2 g NE-30, and 300 g ion exchanged water in a separate one-liter flask at 60[degrees]C for two hours. After an additional two hours, 0.2 g of the initiator ABAP was added to the reaction mixture, which was kept at 70[degrees]C for two hours, as in the monomer dropping method. Characterization of Chitosan-Hybridized Acrylic Emulsions Solid contents of the chitosan-hybridized acrylic emulsions were determined gravimetrically after drying in an air oven at 105[degrees]C for three hours. Particle sizes in the chitosan-hybridized acrylic emulsions were measured by Microtrac-UPA (Nikkiso Co., Ltd.). Viscosities of the chitosan-hybridized acrylic emulsions were determined using a Brook-field Viscometer viscometer Instrument for measuring the viscosity (resistance to internal flow) of a fluid. In one type, the time taken for a given volume of fluid to flow through an opening is recorded. (model BM, Tokimec Inc.) at 25[degrees]C. Minimum film forming temperatures were determined using temperature gradient temperature gradient n. The rate of change of temperature with displacement in a given direction from a given reference point. temperature gradient bars (Shimakawa Inc.) as specified by ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. 2115 standards. Adsorption Tests for Formaldehyde, Hydrogen Sulfide, and Ammonia Adsorption tests for various gases such as formaldehyde, hydrogen sulfide, and ammonia were performed in 20-L chambers at 23[degrees]C. Chitosan-hybridized acrylic emulsions were coated on 15 cm X 15 cm glass plates and dried at room temperature. The two glass plates were put into a chamber and test gas was injected into it. Atmospheric gas concentrations in the chamber were measured by high-performance liquid chromatography, gas chromatography gas chromatography (GC) Type of chromatography with a gas mixture as the mobile phase. In a packed column, the packing or solid support (held in a tube) serves as the stationary phase (vapour-phase chromatography, or VPC) or is coated with a liquid stationary phase , or ion chromatography Ion-exchange chromatography (or ion chromatography) is a process that allows the separation of ions and polar molecules based on the charge properties of the molecules. . Formaldehyde was analyzed as follows (18): A cartridge containing 2,4-dinitrophenylhydrazine (DNPH DNPH 2,4-Dinitrophenylhydrazine ), which forms a derivative with formaldehyde, was connected to chamber outlets to measure the concentration of formaldehyde within the chamber. The DNPH derivative in the DNPH cartridge was dissolved using acetonitrile acetonitrile /ac·e·to·ni·trile/ (as?e-to-ni´tril) a colorless liquid with an etherlike odor used as an extractant, solvent, and intermediate; ingestion or inhalation yields cyanide as a metabolic product. . Formaldehyde concentrations were measured by high-performance liquid chromatography (Shimadzu, LC-10A, column: Intersil ODS-3V 3 X 250 [micro]m, mobile phase: distilled water/acetonitrile = 45/55, detector: UV 360 nm). Hydrogen sulfide was analyzed as follows: The atmosphere from 0.5 ml in the chamber was sampled using a gas-tight syringe. Hydrogen sulfide concentrations were measured by gas chromatography (Yokogawa Analytical Systems Inc. HP5890/HP5921A, column: Pora PLOTQ 25 X 0.32 mm I.D 10 [micro]m film, carrier gas: He, detector: AED AED - Automated Engineering Design wavelength S181 nm 320[degrees]C, He plasma). Ammonia was analyzed as follows: The atmosphere from 1000 ml in the chamber was bubbled in 10 ml of an aqueous solution of 3-mM-methanesulfonic acid. Ammonia concentrations were measured by ion chromatography (Di-onex DX-500, column: ION Pac CS14, mobile phase: 8-mM-methanesulfonic acid, detector: electric conductivity). [FIGURE 4 OMITTED] Coating Formulations The formulation of an interior finishing coating made from chitosan-hybridized acrylic resins is shown in Table 2. Interior finishing coatings were prepared by blending synthesized chitosan-hybridized acrylic emulsions, titanium dioxide, extender See Media Center Extender, bus extender and DOS extender. pigment, and additives, such as dispersing agents, thickeners, and deformers. Ingredients were blended with a mixer at 1200 rpm for 20 min. Mechanical Properties and Coating Characterization Tensile strengths and elongations at breaking points were measured using a universal testing instrument (Autograph AG-10TA from Shimadzu Co.). The tensile speed was 200 mm/min. Specimens were prepared to dumb-bell type 2 test pieces (length of narrow portion: 20 mm, width of narrow portion: 10 mm) at a thickness of 0.5 mm. [FIGURE 5 OMITTED] [FIGURE 6 OMITTED] Tests for the interior finishing coating were evaluated. The drying time test was determined using Ballotini as specified by ISO 1517:1973. The water resistance test and alkali resistance test were conducted according to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. ISO 2812-1:1993. The whole test surface was examined for blistering according to ISO 4628-2:1982. RESULTS AND DISCUSSION Emulsion Polymerization Emulsion polymerizations were carried out by both the monomer dropping method and the pre-emulsion dropping method. In Table 3, characteristics of chitosan-hybridized acrylic emulsions obtained from each emulsion polymerization method and their resin film are shown. In the monomer dropping method, products consisted of high viscosity liquids (4000 mPaxs at 25[degrees]C) and a precipitate, such as a gel, was formed during the polymerization process. On the other hand, chitosan-hybridized acrylic resins prepared by the pre-emulsion dropping method had low viscosities (500 mPaxs at 25[degrees]C) without the formation of any precipitates. These results may reflect that the pre-emulsion dropping method gave homogeneous droplets of monomer mixtures with chitosan. Chitosan-hybridized acrylic resin film forming temperatures were below 0[degrees]C, had excellent water resistance, and did not exhibit water whitening whit·en·ing n. 1. An agent used to make something white or whiter. 2. The act or process of making white or whiter. Noun 1. . These results suggest that chitosan-hybridized acrylic resins are significantly effective materials for interior finishing coatings. Adsorption Ability for Formaldehyde The formaldehyde adsorption abilities by chitosan-hybridized acrylic resin films with various chitosan contents are shown as functions of time in Figure 4. In Figure 2, the initial concentration of formaldehyde in the chamber was 10 ppm and the chitosan content was for the emulsion solid. In the adsorption tests with chitosan-hybridized acrylic resin films, formaldehyde concentrations in the atmosphere lowered to almost 0 ppm in 25 min. On the other hand, in adsorption tests conducted on films without chitosan, formaldehyde concentrations gradually decreased, and after 180 min they reached 0 ppm. After the adsorption tests were finished, the atmosphere in the chamber was replaced with [N.sub.2] gas. Sample films with adsorbed formaldehyde were left at 60[degrees]C for two hours in the chamber, and the formaldehyde concentrations released from these films were measured (Figure 5). In films tested without chitosan, formaldehyde concentrations of about 4 ppm were recognized. This may be caused by the adsorption of formaldehyde onto film surfaces. In chitosan-containing films, formaldehyde was not detected in the least. Figure 6 shows FTIR FTIR Fourier Transform Infrared (spectroscopy) FTIR Frustrated Total Internal Reflection FTIR Fourier Transfer Ir spectra of chitosan-hybridized acrylic resins before and after formaldehyde adsorption. In chitosan-hybridized acrylic resins (Figure 6c), strong and weak peaks based on acrylic resins and chitosan were observed at 1720 [cm.sup.-1] and 1150 [cm.sup.-1], respectively. Moreover, chitosan-hybridized acrylic resins had weak amino group bands at 1580 [cm.sup.-1]. On the other hand, in chitosan-hybridized acrylic resins, adsorbed formaldehyde (Figure 6d) peaks based on amino groups were not observed because of the combination of chitosan and formaldehyde. It was difficult to directly verify the combination of chitosan and formaldehyde in chitosan-hybridized acrylic resins because characteristic absorption bands from chitosan-hybridized acrylic resins overlap acrylic resins bands. Therefore, FTIR spectra of chitosan before and after adsorption tests for formaldehyde were measured (Figures 6a and 6b). Both chitosans had peaks based on pyranose rings and acetyl acetyl /ac·e·tyl/ (as´e-til) (as´e-tel?) (ah-se´til) the monovalent radical CH3COsbond, a combining form of acetic acid. a·ce·tyl n. amino groups. Chitosan showed a peak based on the amino group band at 1580 [cm.sup.-1]. Chitosan-adsorbed formaldehyde did not show a peak from amino groups, but instead showed a peak based on a C=N stretch at 1550 [cm.sup.-1]. Schiff's bases (-N=C[H.sub.2]) were made from chitosan amino groups and formaldehyde, as shown in Figure 7. These results suggest that formaldehyde is not released from chitosan-hybridized acrylic resin films, which can be attributed to the fact that formaldehyde had reacted with chitosan amino groups in the resins. Adsorption Ability for Hydrogen Sulfide and Ammonia Adsorption performance results from chitosan-hybridized acrylic resin films with 5 wt% chitosan contents for hydrogen sulfide and ammonia gases are shown in Figure 8. Initial concentrations of hydrogen sulfide and ammonia were 50 ppm and 20 ppm, respectively. The concentration of hydrogen sulfide decreased with time and reached 30 ppm after 24 hr. In the case of ammonia, the ammonia concentration reached 0 ppm after 24 hr. However, a film-dispersed chitosan could not adsorb adsorb /ad·sorb/ (ad-sorb´) to attract and retain other material on the surface; to conduct the process of adsorption. ad·sorb v. To take up by adsorption. hydrogen sulfide and ammonia. From these results, it was found that hydrogen sulfide and ammonia could also be adsorbed into chitosan-hybridized acrylic resin films. It is presumed that hydrogen sulfide and ammonia may electrostatically interact with carbonyl groups in chitohan-hybridized acrylic resin film. Mechanical Properties The mechanical properties of chitosan-hybridized acrylic resin films are summarized in Table 4. The percentages of chitosan listed in Table 4 are for the weight in the emulsion polymerization. Tests were performed at -5[degrees]C and 23[degrees]C. As can be seen from the results, mechanical properties were remarkably dependent on acrylic resin contents. The tensile strengths and elongations at breaking points of chitosan-hybridized acrylic resin films were lower than those of acrylic resin films and decreased with increasing chitosan contents. Decreases in tensile strength and elongation at breaking points with the addition of chitosan to emulsion polymerizations are due to the following: in copolymerizations of emulsion polymerizations of chitosan-AA salts, MMA, and 2EHA with chitosan, molecular weights of AA-MMA-2EHA copolymers are lower than that of copolymers in the emulsion polymerization of AA, MMA, and 2EHA without chitosan. This is because AA forms complexes with chitosan and, consequently, copolymerizations of AA with MMA and 2EHA are limited. It is presumed that decreases in the molecular weights of AA, MMA, and 2EHA copolymers causes a decrease in mechanical strength. [FIGURE 7 OMITTED] [FIGURE 8 OMITTED] Characteristics of Chitosan-Hybridized Acrylic Resin Finishing Coatings An interior finishing coating without volatile organic compounds, such as a film forming solvent, was prepared using chitosan-hybridized acrylic emulsions with 5 wt% chitosan contents. The pigment volume concentration in this coating was 60%. Table 5 shows the adsorption performance of the chitosan-hybridized acrylic resin finishing coating for formaldehyde in different concentrations. Under both conditions, formaldehyde concentrations became about 0.1 ppm after 24 hr. These results support that interior finish coatings with chitosan-hybridized acrylic resins have excellent adsorption abilities for formaldehyde. Tests for interior finishing coatings with chitosan-hybridized acrylic resins were carried out. The results, summarized in Table 6, show that finishing coatings made from chitosan-hybridized acrylic resin emulsions have the necessary qualities for interior finishing coatings. CONCLUSION In the present work, chitosan-hybridized acrylic resins were developed for application in interior finishing coatings. We investigated emulsion polymerizations for chitosan, which is an effective natural polymer that has formaldehyde adsorption abilities. Chitosan-hybridized acrylic emulsions made by the pre-emulsion dropping method showed good stability. Chitosan-hybridized acrylic resin films showed high adsorption abilities for formaldehyde, hydrogen sulfide, and ammonia. Tensile strengths and elongation at breaking points of the chitosan-hybridized acrylic resins decreased with increasing chitosan contents. Nonetheless, interior finishing coatings made from chitosan-hybridized acrylic resin emulsions with 5 wt% chitosan contents have the necessary qualities for an interior finishing coating and showed excellent adsorption abilities for formaldehyde.
Table 1 -- Components of Emulsion Polymerization
Component Content
MMA 10.50 wt%
2EHA 21.27 wt%
AA 0.52 wt%
Chitosan 1.29 wt%
Nonionic surfactants 2.20 wt%
Ion exchanged water 64.10 wt%
Initiator 0.12 wt%
Total 100.00 wt%
Table 2 -- Formulation of the Interior Finishing Coatings
Ingredient wt%
Chitosan-hybridized acrylic emulsions 45.0
Deionized water 4.4
Dispersant (Poise 521, Kao Co., Ltd., Japan) 1.0
Extender pigment (Whiting limestone powder, Maruo Calcium Co., 27.0
Ltd., Japan)
Titanium dioxide (Tioxide TR-92, Tioxide Japan Co., Ltd., Japan) 21.0
Thickeners (Adekanol UH-420, Asahi Denka Co., Ltd., Japan) 0.8
Thickeners (Adekanol UH-472, Asahi Denka Co., Ltd., Japan) 0.8
Total 100.0
Table 3 -- Characteristics of Chitosan-Hybridized Acrylic Emulsions and
Polymer Films
Pre-Emulsion
Test Monomer Dropping Method Dropping Method
Viscosity 4000 mPa*s at 500 mPa*s at
25[degrees]C 25[degrees]C
Polymer gel (on 100 mesh) Present Absent
Solids content 27.0% 34.0%
pH 5.8 5.7
Average particle size -- 204.6 nm
Minimum film forming -- Below 0[degrees]C
temperature
Film appearance -- Clear film (Glossy)
Table 4 -- Mechanical Properties of Chitosan-Hybridized Acrylic Resin
Films with Different Chitosan Contents
Tensile Strength Elongation at Breaking Point
Chitosan (N/[mm.sup.2]) (%)
Content wt% -10[degrees]C 23[degrees]C -10[degrees]C 23[degrees]C
0 13.5 1.3 260 610
1 12.0 1.2 230 600
2 10.5 1.2 210 590
3 10.0 1.2 190 560
4 9.3 1.2 170 400
5 7.4 0.6 150 380
Table 5 -- Adsorption Performance of Chitosan-Hybridized Acrylic Resins
Finishing Coatings (a) for Formaldehyde
Initial Concentration After 24 hr
3.32 ppm 0.11 ppm
19.65 ppm 0.14 ppm
(a) Pre-emulsion method
Table 6 -- Characteristics of Interior Finish Coatings with Chitosan-
Hybridized Acrylic Resins
Test Quality Standard Result
In-can appearance Becomes homogeneous when Homogeneous
stirred
Application properties Forms a uniform dry film No impediment
Low-temperature stability No deterioration No deterioration
at wet paint
Drying time Within 2 hr at 40 min
20[degrees]C
Within 4 hr at 75 min
5[degrees]C
Dry film appearance No appearance defects No deterioration
Water resistance No failure when immersed Degree of
in water for 96 hr blistering 0 (More
than 168 hr)
Alkali resistance No failure when immersed Degree of
in calcium hydrate for blistering 0 (More
48 hr than 120 hr)
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