Acrylic blends

Since most of the applications of the PMMA type acrylic resins are based on their high degree of transparency and UV resistance characteristics, there has been little commercial interest or motivation in developing acrylic blends. This is understandable because unless there is complete, molecular level miscibility between the components, it is not possible to maintain a high degree clarity in the blends. Nevertheless, several examples of commercial blends of acrylic resins are known. These will be discussed under separate headings. 

Since the homopolymer PMMA as well as the MMA-rich copolymers are quite brittle, exhibiting low elongation to break 5%) and low notched Izod impact strength (typically 15 J/m), there was a need to blend suitable impact modifiers that would improve the ductihty and impact strength of these resins without sacrificing the transparency, rigidity and weatherabihty characteristics. 

Two general types of impact modified acryhc resins have been developed commercially, viz. (a) weatherable, impact modified, transparent acryhc resins for outdoor use in signs and automobiles  

Commercial impact modihed acrylic resins (Table 15.11) exhibit 5 to 10 fold improvement in the notched Izod impact strength and the ultimate tensile elongation compared to the neat PMMA resin. These impact modified acrylics are 

Blend Type ACRYLIC/IMPACT MODIFIER ACRYLIC 

Polymethylacrylate (PMA) and polymethylmethacrylate (PMMA) were discovered, respectively, in 1880 and 1930. The resins have been used for the production of transparent plastic sheets, viz., Plexiglas or Perspex , and used for the military aircraft cockpit canopies, gunner s turrets, and the like (Riddle 1954). Acrylic elastomers (ACM or ANM) were developed by Rohm in 1901 and commercialized in 1948 as Hycar vulcanizable copolymers of ethyl acrylate, allyl maleated lactones, chloroethyl vinyl ether, butadiene, isoprene, acrylonitrile, etc. (Mast et al. 1944). Since the 1950s, a wide variety of acrylic compatibilizers and impact modifiers have been developed. 

Methylmethacrylate-butadiene-styrene terpolymer (MBS) Fujii and Ohtsuka 1954 

Partially cross-linked ABS core and PMMA shell (a MABS) Michel 1969 

In the 1950s, the core-shell, emulsion-type methylmethacrylate-butadiene-styrene terpolymer (MBS) was developed to toughen PVC or PC. These blends could also contain other polymers, viz., SAA (Murdock et al. 1960), SMM and PS (Murdock et al. 1962), SMM-AN (Schmitt et al. 1967), high heat ABS (Kanegafuchi Chemical Industry 1967), HIPS (Ward 1970), MMVAc-AA (Holland et al. 1970), SMMA (Blasius 1992), etc. Table 1.33 traces the evolution of these systems. Later, these multipolymers were modified by incorporation of MA, AA, or GMA units to serve as reactive compatibilizers and toughening agents for PA, PEST, or PC blends. 

like PS, is brittle and requires toughening. These efforts are summarized in Table 1.34. 

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Wool-acrylic blends Wool combing Wool-cotton blends Wool dyes Woolen systems... 

The versatility of this system is reflected in its suitability for blends of wool with other fibres [89]. The ideal conditions for the dyeing of wool/acrylic blends are at pH 4-5 and Albegal SET inhibits the risk of co-precipitation between Lanaset anionic dyes and basic dyes. Lanaset dyes are quite stable when dyeing polyester/wool at pH 4-5 and 115-120°C using Irgasol HTW (Ciba) as wool protectant. These dyes are also suitable for dyeing wool in its blends with silk, nylon or cellulosic fibres. 

Polyester Fiber-Acrylic Fiber Blends. This liber blend is dyed in a similar fashion to that of the blends of the different polyester fibers. The selection of cationic dyes is substantially larger for the acrylic blend. 

Promotes reserving of component fibers in acrylic blends when dyeing with cationic dyes... 

Is a strongly hydrophilic emulsifier, dispersant, solubilizer and detergent. It is used as a stabilizer and anticoagulant for natural and synthetic latices and dye pastes, as a dyeing assistant for wool/acrylic blends, and as a detergent and lubricant for fiber/fabric scouring. TRYCOL 5972 is also used as an emulsifier for waxes used in coating citrus fruits. HLB 15.8... 

A lubricant for spinnig acrylic blends into yarn. PROGALUBE 95 has good fiber-to-metal lubricity and helps soften harsh fibers during spinning. 

Low-molecular-weight oligomers (10,000 to 20,000) with 75% conversion rate have been synthesized photochemically from BrCCI —CH Br with an acrylate blend (Ethyl and butyl). 

Polyesters also are used in various polymer blends such as polycarbonate/poly(butylene terephthalate), poly(butylene terephthalate/acrylonitrile-styrene-acrylic) blends, poly(vinyl chloride)/poly(ethylene terephthalate), etc. Pyrolysis results on poly(vinyl chloride)/ poly(ethylene terephthalate) have been reported [64] showing that the two components influence each other, chloroesters of terephthaiic and benzoic acids being found in the pyrolysate. 

Defoort B., Lopitaux G., Dupillier J.M., Larnac G., Coqueret X., Electron-beam initiated polymerization of acrylate compositions, 6 Influence of processing parameters on the curing kinetics of an epoxy acrylate blend, Macromol. Chem. Phys., 2001,202,3149-3156. 

Viscose/Regenerated Solution is same as for viscose/acrylic blend 30... 

For polyamide/acrylic blends, both the fibres can be brightened by using suitable disperse type brighteners at 95-98 C for 30-60 min, cooled, rinsed well and dried. Where bleaching is necessary, a suitable brightener stable to chlorite may be included in the bleach bath. 

Macrobase. [Sartomer] Polystyrene/ acrylate blends dispersant for pigments used in uv/eb curable adhesives. 

Figure 1. Notched Izod of PVC/acrylic blends vs. concentration of acrylonitrile in the acrylic...

Examples of commercial PVC/acrylics blends are Acrylivin , Decoloy , Enplex , Hostalit , Kane-ace , Kydene Metabulen or Vinidur . The blends have been used for industrial, commercial, and consumer goods, in medical, electrical, and chemical engineering equipment, for food... 

PMMA is antagonistically immiscible with a polyolefins — blends of this type have been used in non-critical applications, viz. PP/PMMA blends with EVAc were used as plastic-paper [Yamamoto et al., 1971], while those with PVC (or CA) as wood-like materials [Yahata et al., 1971]. For more demanding applications, either PO should be blended with an acrylic copolymer comprising a PO block, or PO should be grafted with acrylic moieties. Examples of the PO/Acrylics blends are listed in Table 1.36. 

PVDF with PMMA, PEMA, PMHA copolymers The binary interaction parameter B(caiymL) was negative for all PVDC/acrylate blends Goh and Slow, 1988... 

LDPE/EPDM/CB Blends Jia and Chen [1994] investigated the effect of irradiation on the positive temperature coefficient (PTC) function of LDPE/EPDM and LDPE/EEA (ethylene-ethyl acrylate) blends containing carbon black. They used LDPE, EPDM, EEA and CSF carbon black (Table 11.9) in the desired ratios and mixed them in a two-roU mill in an internal mixer at 130°C for 5 min. The samples were molded under pressure at 160°C for 10 min. 

Figure 14.18. ATR spectra for polyester-acrylic blends under quick ultra violet exposure.

Figure 14.20. XPS spectra for uastabilized polyurethane-acrylic blends for zero (upper) and 43 days (lower) quick ultra...

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