Dispersion acrylic table

Commercial impact-modified acrylic resins (Table 19.15) exhibit five- to tenfold improvement in the notched Izod impact strength and the ultimate tensile elongation compared to the neat PMMA resin. These impact-modified acrylics are usually blended captively by the manufacturers of the acrylic resins. The base resin in a typical weatherable grade (Plexiglas DR, Rohm and Haas) could be a methyl methacrylate copolymer with ethylacrylate and styrene, while the rubber additive (ca. 10 %) could be an emulsion-polymerized, PMMA-grafted, cross-linked poly (n-butylacrylate) rubber of controlled particle size (<200 nm). The nonweatherable impact-modified acrylic (XT, CYRO) typically consists of a MMA/S/AN copolymer with MBS (ca. 10 %) rubber particle dispersions. 

Table 2. Differences between solvent-based (alkyd paint) and water-based paints (acrylic dispersion paint) (Van Faassen and Borm 1991)...

In the table 1 physical and mechanical characteristics of the inflated with organic and inorganic fillers acryUc compounded mix based on A4 acrylic dispersion are presented. The same behavior of samples based on the other acrylic dispersions was revealed. 

The manufacture of polymer dispersions is a complex multi-stage process involving a large number of raw materials and several stages as the example below (Table 4), for the production of a styrene-acrylic dispersion shows (CRI, 2002). 

TABLE 8.5 Properties of Some Com Otherwise Indicated) continued mercial Acrylic Dispersions Used in Conservation (Manufacturer s Information Unless ... 

The sulfosuccinates must be individually evaluated under varying conditions to obtain optimum results. For example, disodium laureth-5 sulfosuccinate (DLFS) is excellent for finely dispersed lattices styrene-homo- and copolymers, styrene-acrylate copolymers, acrylate-homo- and copolymers, and vinyl acetate-homo-and copolymers. DLFS is used in a concentration (related to monomer) of 3-5%. Table 19 shows possible application areas of dialkyl sulfosuccinates. 

The use of DQ4 in the desliming stage has a significant impact on monazite loss to the slime fraction. Table 24.15 shows the effect of different dispersants on monazite loss in the slime fraction, using dispersants from the DQ series. These dispersants are a mixture of low-molecular-weight acrylic acids modified with surfactant. 

Reactive impact modifiers are preferred for toughening of PET since these form a stable dispersed phase by grafting to the PET matrix. Non-reactive elastomers can be dispersed into PET by intensive compounding but may coalesce downstream in the compounder. Reactive impact modifiers have functionalized end groups. Functionalization serves two purposes - first, to bond the impact modifier to the polymer matrix, and secondly to modify the interfacial energy between the polymer matrix and the impact modifier for enhanced dispersion. Some examples of commercially available reactive impact modifiers for PET are shown in Table 14.3. An example of a non-reactive elastomer that can be used in combination with reactive impact modifiers is ethylene methyl acrylate (EMA), such as the Optema EMA range of ethylene methyl acrylates manufactured by the Exxon-Mobil Chemical Company (see Section 4.2). 

As shown In Tables IV and V, copolymers were quite effective in dispersing iron oxide and clay as compared to polyacrylic acid. Among the polymers tested, acrylic acid/N-(2-hydroxyethyl)acrylamide seemed to be the most effective. 

The split into the various textile dyestuff application areas has, over recent years, seen a shift towards the two main outlets of disperse dyes for polyester and reactive dyes for cellulosics (mainly cotton), at the expense of directs and vat dyes for cotton, cationic dyes for acrylics and acid dyes for polyamide. The latter fibre has shown a comeback in recent years with the popularity of microfibres in sports and leisure wear. The position in 1998, with disperse dyes dominating in value terms, was as shown in Table 2.6. 

Typical formulations of oil-less toners utilizing COCs are shown in Table 2.5. The compatibility with other resins and the pigment dispersibility can be improved by introducing carboxyl groups into the COC by the fusing air oxidation method, maleic anhydride modification, or acrylic acid modification (53). 

The two extremes on the styrene-butadiene block copolymer composition scale are homopolymers of butadiene or styrene, respectively. To test the usefulness of homopolymers as dispersants, polybutadiene (PB) was carboxylated by adding thioglycolic acid, and polystyrene (PS) having carboxylic groups was prepared by copolymerizing small amounts of acrylic acid (AA) into the styrene chain. Adsorption experiments with these carboxylated homopolymers are listed in Table V. In the first... 

Polarity of Vinyl Acrylic Latex and Surfactant Adsorption Contact angle measurements, dispersion and polar contribution to latex film surface tension and polarity of polymer calculated according to the method of Kaelble (10) of the three latex films are whown in Table V. It is seen that the polarity of the latex film decreases with increase in butyl acrylate content of the vinyl acrylic co-polymer. The polarity of the 70/30 (VA/BA) latex is very similar to that of the polybutyl acrylate homopolymer estimated to be about 0.21 (1). ... 

Both aqueous polymer-based systems (latex), made by emulsion or dispersion polymerization, and oil-modified alkyd resin-based systems are still in wide use [781], Table 12.2 shows the composition of a typical water-based emulsion paint. There is a wide variety of coatings, ranging from broad applicability to highly specialized, including latexes, amino resins, isocyanates, epoxy resins, acrylic resins, polyester... 

Most research into the study of dispersion polymerization involves common vinyl monomers such as styrene, (meth)acrylates, and their copolymers with stabilizers like polyvinylpyrrolidone (PVP) [33-40], poly(acrylic acid) (PAA) [18,41],poly(methacrylicacid) [42],or hydroxypropylcellulose (HPC) [43,44] in polar media (usually alcohols). However, dispersion polymerization is also used widely to prepare functional microspheres in different media [45, 46]. Some recent examples of these preparations include the (co-)polymerization of 2-hydroxyethyl methacrylate (HEMA) [47,48],4-vinylpyridine (4VP) [49], glycidyl methacrylate (GMA) [50-53], acrylamide (AAm) [54, 55], chloro-methylstyrene (CMS) [56, 57], vinylpyrrolidone (VPy) [58], Boc-p-amino-styrene (Boc-AMST) [59],andAT-vinylcarbazole (NVC) [60] (Table 1). Dispersion polymerization is usually carried out in organic liquids such as alcohols and cyclohexane, or mixed solvent-nonsolvents such as 2-butanol-toluene, alcohol-toluene, DMF-toluene, DMF-methanol, and ethanol-DMSO. In addition to conventional PVP, PAA, and PHC as dispersant, poly(vinyl methyl ether) (PVME) [54], partially hydrolyzed poly(vinyl alcohol) (hydrolysis=35%) [61], and poly(2-(dimethylamino)ethyl methacrylate-fo-butyl methacrylate)... 

The oil structure influence on the formulation is illustrated in Figure 1. It represents the minimum percentage of emulsifiers required to induce the transition aacro-raicroeaulsion versus their HLB values for monomer-water mixtures dispersed in different oils. It can be seen that in the case of acrylamide (AH) or acrylamide-sodium acrylate (Aa) mixtures, the amount of surfactant needed to form a microemulsion is much larger for toluene or cyclohexane than for Isopar K (11,12[). When methacrylcxyethyltrimethylammonium chloride (HA0OU.AT) is the monomer, the optimal conditions are obtained in cyclohexane. These results closely follow the differences calculated for the solubility parameters between oils and lipophiles as shown in Table I. 

The properties of thermosetting and thermoplastic resin systems are continually improved to meet increasing performance requirements of end users. One way to enhance material properties is to incorporate nano-modifiers, based on elastomeric silicone particles, which are optionally grafted with other (acrylic) polymers to control dispersibility, viscosity, and other parameters. As an example, epoxy resin formulations have been modified with silicone nanospheres to improve low-stress behavior. Table 1 shows the outstanding fracture toughness improvement of silicone coreshell nanospheres, even at very low particle loading levels. 

The minimum requirements for a dispersion polymerization are monomer, solvent/nonsolvent, initiator, and steric stabilizer. The monomer must be soluble in the reaction mixture and its polymer, insoluble. The monomers used in systems of commercial interest are methyl methacrylate, vinyl chloride, vinyli-dene chloride, vinyl esters, hydroxyl alkyl acrylates. A typical recipe for dispersion polymerization is shown in Table 9. 

In a thermoplastic acrylic automotive coating, a CAB is used as the pigment dispersion medium and at 15% concentration based on polymer weight provides better sprayability, increased cold crack resistance, better pigment control, better solvent release, and improved exterior durability. (See Table IX.)... 

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