Acrylic acid Acrylics, polymer manufacture

Acrylic Acid, Acrylates, and Acrylonitrile. Acrylic acid [79-10-7], C3H402, and acrylates were once prepared by reaction of acetylene and carbon monoxide with water or an alcohol, using nickel carbonyl as catalyst. I11 recent years tliis process has been completely superseded in the United States by newer processes involving oxidation of propylene (2). I11 western Europe, however, acetylene is still important in acrylate manufacture (see Acrylic acid and derivatives Acrylic ester polymers). 

Poly(acrylic acid) A polymer of acrylic acid used as a sizing agent in the manufacture of nylon and other synthetic textiles See image). 

The principal monomer used in the manufacture of superabsorbent polymers is acrylic acid. Acrylic acid is made by the oxidation of propene in two steps (5). First, propene is oxidized to acrolein, and then the acrolein is further oxidized to aciylic acid. Different mixed metal oxide catalysts are used for each step to optimize the yield and selectivity of the oxidation reactions. Technical-grade acrylic acid is isolated from the steam-quenched reaction gas by means of solvent extraction and distillation, and is used principally in the fiirther preparation of acrylate esters. The technical-grade acrylic acid is further purified by distillation or by crystallization from the melt to afford the polymerization-grade monomer. 

CHi=CMeCOOH. Colourless prisms m.p. 15-16 C, b.p. 160-5 C. Manufactured by treating propanone cyanohydrin with dilute sulphuric acid. Polymerizes when distilled or when heated with hydrochloric acid under pressure, see acrylic acid polymers. Used in the preparation of synthetic acrylate resins the methyl and ethyl esters form important glass-like polymers. 

CHjlCH COOH. Colourless liquid having an odour resembling that of ethanoic acid m.p. 13 C, b.p. I4I°C. Prepared by oxidizing propenal with moist AgO or treating -hy-droxypropionitrile with sulphuric acid. Slowly converted to a resin at ordinary temperatures. Important glass-like resins are now manufactured from methyl acrylate, see acrylic resins. Propenoic acid itself can also be polymerized to important polymers - see acrylic acid polymers. 

The polymeric products can be made to vary widely in physical properties through controlled variation in the ratios of monomers employed in thek preparation, cross-linking, and control of molecular weight. They share common quaHties of high resistance to chemical and environmental attack, excellent clarity, and attractive strength properties (see Acrylic ester polymers). In addition to acryHc acid itself, methyl, ethyl, butyl, isobutyl, and 2-ethylhexyl acrylates are manufactured on a large scale and are available in better than 98—99% purity (4). They usually contain 10—200 ppm of hydroquinone monomethyl ether as polymerization inhibitor. 

Polymer Composition. Ethylene—acrylic elastomer terpolymers ate manufactured by the addition copolymerization of ethylene [74-85-1] and methyl acrylate [96-33-3] in the presence of a small amount of an alkenoic acid to provide sites for cross-linking with diamines (4). 

For acrylate polymers with higher levels of carboxylic acids, THF can be modified by the addition of acids such as acetic, phosphoric, or trifluoroacetic. Levels as high as 10% acetic acid are considered acceptable by most manufacturers for their styrene/DVB columns. If such a modified mobile phase is used, it may need to be premixed rather than generated using a dynamic mixing HPLC pump because on-line mixing often leads to much noisier baselines, particularly when using a refractive index detector. 

Manufacture of highly water-absorbent polymers with uniform particle size and good flowability can be carried out by reverse phase suspension polymerization of (meth)acrylic acid monomers in a hydrocarbon solvent containing crosslinker and radical initiator. Phosphoric acid monoester or diester of alka-nole or ethoxylated alkanole is used as surfactant. A polymer with water-absorbent capacity of 78 g/g polymer can be obtained [240]. 

Three major non-polymer propylene derivatives are isopropanol, acetone, and acrylic acid. Isopropanol (isopropyl alcohol) is used mainly as a solvent. It has been made from propylene by reaction with sulfuric acid and water for at least the last 75 years, making its manufacture the oldest, still-running commercial organic chemical process. It is used in household rubbing alcohol because, unlike ethanol, it is unfit for human consumption even in small amounts. About 25 % of the isopropanol produced is used for making acetone, in competition with a route based on isopropylbenzene. 

Applications As the basic process of electron transfer at an electrode is a fundamental electrochemical principle, polarography can widely be applied. Polarography can be used to determine electroreductible substances such as monomers, organic peroxides, accelerators and antioxidants in solvent extracts of polymers. Residual amounts of monomers remain in manufactured batches of (co)polymers. For food-packaging applications, it is necessary to ensure that the content of such monomers is below regulated level. Polarography has been used for a variety of monomers (styrene, a-methylstyrene, acrylic acid, acrylamide, acrylonitrile, methylmethacrylate) in... 

Poly(acrylic acid) is water soluble. Because of its water solubility and its ability to increase the viscosity of water, it is used as a thickener. It is also a good flocculent for sewage treatment and is added as a pigment dispersant in latex paints, and is used in binders and adhesives. Polymers and copolymers containing acrylic or/and methacrylic acid are manufactured at a rate of about 2,000,000 metric tons yearly. 

Acrylic acid [79-10-7] - [AIR POLLUTION] (Vol 1) - [ALDEHYDES] (Vol 1) - [ALLYL ALCOHOL AND MONOALLYL DERIVATIVES] (Vol 2) - [MALEIC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) - [POLYESTERS, UNSATURATED] (Vol 19) - [FLOCCULATING AGENTS] (Vol 11) - [CARBOXYLICACIDS - SURVEY] (Vol 5) -from acetylene [ACETYLENE-DERIVED CHEMICALS] (Vol 1) -from acrolein [ACROLEIN AND DERIVATIVES] (Vol 1) -acrylic esters from [ACRYLIC ESTER P OLYMERS - SURVEY] (Vol 1) -from carbon monoxide [CARBON MONOXIDE] (Vol 5) -C-21 dicarboxylic acids from piCARBOXYLIC ACIDS] (Vol 8) -decomposition product [MAT. ETC ANHYDRIDE, MALEIC ACID AND FUMARIC ACID] (Vol 15) -economic data [CARBOXYLIC ACIDS - ECONOMIC ASPECTS] (Vol 5) -ethylene copolymers [IONOMERS] (Vol 14) -in floor polishes [POLISHES] (Vol 19) -in manufacture of ion-exchange resins [ION EXCHANGE] (V ol 14) -in methacrylate copolymers [METHACRYLIC POLYMERS] (Vol 16) -in papermaking [PAPERMAKING ADDITIVES] (Vol 18)... 

Vinyl ester resins arc manufactured through an addition reaction of an epoxy resin with an acrylic monomer, such as acrylic acid, methaciylic add. or the half-ester product of an hydroxyalkyl acrylate and anhydride. In contrast, the polyester resins are condensation products of dibasic acids and palyhydric alcohols. The relatively low-molecular-weight precise polymer structure of the vinyl ester resins is in contrast to the high-molecular-weight random structure of the polyesters. 

PVC can be blended with numerous other polymers to give it better processability and impact resistance. For the manufacture of food contact materials the following polymerizates and/or polymer mixtures from polymers manufactured from the above mentioned starting materials can be used Chlorinated polyolefins blends of styrene and graft copolymers and mixtures of polystyrene with polymerisate blends butadiene-acrylonitrile-copolymer blends (hard rubber) blends of ethylene and propylene, butylene, vinyl ester, and unsaturated aliphatic acids as well as salts and esters plasticizerfrec blends of methacrylic acid esters and acrylic acid esters with monofunctional saturated alcohols (Ci-C18) as well as blends of the esters of methacrylic acid butadiene and styrene as well as polymer blends of acrylic acid butyl ester and vinylpyrrolidone polyurethane manufactured from 1,6-hexamethylene diisocyanate, 1.4-butandiol and aliphatic polyesters from adipic acid and glycols. 

The drag is distributed throughout a polymer matrix. Such a system can be relatively easy to manufacture, the simplest case being when the drag is dispersed directly in a blend composed of, for example, a mixture of poly(acrylic acid) and elastomeric compounds such as poly(isobutylene) and poly(isoprene). 

Commercial acrolein is an intermediate in the manufacture of several products, in particular D,L-methionine, used as an additive in animal feeds. For the most part however it is directly oxidized to acrylic acid, without being separated and recovered as a pure material. The acid is mainly esterified to methyl and other acrylates, with the remainder being directly used for the manufacture of polymers. Acrylate esters are currently the final destination of most acrolein produced in the world. They readily form homopolymers and copolymerize with methacrylates, styrene, vinyl acetate and acrylonitrile to yield a range of prized products, characterized by excellent clarity, stability to UV light and aging, and good pigmentability. 

Polymers based on acrylic acid are highly hydrophilic and are utilized in different applications that include superadsorbent materials, flocculants and dispersants. Polyacrylates and their copolymers range from soft and flexible materials to hard plastics, applied in the production of coatings, paints, binders and adhesives. Their applications include the manufacture of cars e.g., coatings, upholsteries and adhesives) and the textile e.g., binders for fiberfill and nonwoven fabrics), paper and leather industries. Methyl acrylate is mainly utilized for copolymerization with acrylonitrile to improve the dyeability of fibres. 

Carbomers are synthetic, high-molecular-weight, crosslinked polymers of acrylic acid. These poly(acrylic acid) polymers are crosslinked with allyl sucrose or allyl pentaerythritol. The polymerization solvent used most commonly was benzene however, some of the newer commercially available grades of carbomer are manufactured using either ethyl acetate or a cyclohexane-ethyl acetate cosolvent mixture. The Carbopol ETD resins are produced in the cosolvent mixture with a proprietary polymerization aid, and these resins are crosslinked with a polyalkenyl polyether. 

---