Acid comonomers

Most commercial processes involve copolymerization of ethylene with the acid comonomer followed by partial neutralization, using appropriate metal compounds. The copolymerization step is best carried out in a weU-stirred autoclave with continuous feeds of all ingredients and the free-radical initiator, under substantially constant environment conditions (22—24). Owing to the relatively high reactivity of the acid comonomer, it is desirable to provide rapid end-over-end mixing, and the comonomer content of the feed is much lower than that of the copolymer product. Temperatures of 150—280°C and pressures well in excess of 100 MPa (1000 atm) are maintained. Modifications on the basic process described above have been described (25,26). When specific properties such as increased stiffness are required, nonrandom copolymers may be preferred. An additional comonomer, however, may be introduced to decrease crystallinity (10,27). 

Itaconic acid is a specialty monomer that affords performance advantages to certain polymeric coatings (qv) (see Polyesters, unsaturated). Emulsion stabihty, flow properties of the formulated coating, and adhesion to substrates are improved by the acid. Acrylonitrile fibers with low levels of the acid comonomer exhibit improved dye receptivity which allows mote efficient dyeing to deeper shades (see Acrylonitrile polymers Fibers, acrylic) (10,11). Itaconic acid has also been incorporated in PAN precursors of carbon and graphite fibers (qv) and into ethylene ionomers (qv) (12). 

In the case of an acrylate PSA containing an acidic comonomer, there is the... 

Ionomers are made in a two-stage process. In the first step, we copolymerize ethylene with small amounts of an organic acid containing a vinyl group, such as acrylic or methacrylic acid, in a high pressure reactor. In the second step, we neutralize the acid comonomers to form metal salts. We can create ionomers with a variety of metal salts, including sodium, calcium, and zinc. 

The carboxylated polymers [476,499] include acrylic, methacrylic or maleic acid polymers (all obviously anionic in character) applied mainly from aqueous emulsion and particularly in combination with crease-resist or durable press resins. This type of chemistry has already been discussed in section 10.8.2. A particularly common example is the copolymer of acrylic acid with ethyl acrylate (10.247). In general the best balance of properties is obtained with 75-85% ethyl acrylate (y) and 25-15% acrylic acid (x), with an average chain length of about 1300 (x + y) units 65-85% ethyl acrylate with 35-15% methacrylic acid is also suitable. When the content of the acidic comonomer increases above about 30% the durability to washing tends to decrease, whilst longer chains tend to give a stiffer handle [499]. 

Base copolymers with dicarboxylic acid comonomers, even those in which one acid radical has been esterified, when neutralized with metal ions, which have two or more ionized valences, result in intractable ionic copolymers at the level of neutralization essential to obtain significant improvement in solid state properties. 

Similarly, base copolymers with mono-carboxylic acid comonomers result in intractable ionic copolymers when neutralized to the indicated degree with metal ions, which have four or more ionized valences. It is believed that the nature of the ionic bond in these instances is too strong to be suitable for the formation of ionic copolymers, which exhibit solid state properties of crosslinked resins and melt properties of uncrosslinked resins. 

Manufacture and Processing. Most commercial processes involve copolymerizaiion of ethylene with the acid comonomer followed by partial neutralization, using appropriate metal compounds. 

Procter Gamble is the other leading pioneer on the field of PHA biodegradable polymers. The Nodax biopolymers are based on the copolymer PHBH, a copolymer polyester of 3-hydroxybutyric and 3-hydroxyhexanoic acid. The higher the 3-hydroxyhexanoic acid comonomer component, the more flexible... 

A thermosetting appliance enamel consists of a terpolymer comprising about 72 parts of vinyl toluene (70/40 meta/para) with about 20 parts of ethyl acrylate (to reduce brittleness of the copolymer) and 8 parts of an acidic vinyl comonomer. The acid is incorporated in the copolymer to provide sites for subsequent cross-linking with a diepoxide. It seems reasonable to expect that grease and slain resistance of the cross-linked enamel will be enhanced if the cross-links are not clustered and almost all initial polymer molecules contain at least one or a few cross-linking sites. To achieve this in a batch copolymerization, what are the best reactivity ratios (approximately) of the major component (vinyl toluene) and the vinyl acid comonomer Show you reasoning. 

In the absence of ionic species (e.g. acidic comonomers such as itaconic acid or acrylic acid, or anionic additives such as alcoholates), the main initiation of the CN oligomerization in PAN and its copolymers is then, most probably, a radical... 

In Fig. 3 the temperature-dependent swelling behaviour for PNIPAAm copolymer gels with different amounts of acidic comonomer (e.g. AAmPA 2 corresponds to 2 mol-% of AAmPA) is shown. In de-ionized (DI) water the comonomer is partly... 

M.B. Huglin, Y. Liu and J.L. Velada, Thermoreversible swelling behavior of hydrogels based on /V-isopropylacrylamide with acidic comonomers, Polymer, 1997, 38, 5785 M.K. Yoo, Y.K. Sung, C.S. Cho and Y.M. Lee, Effect of polymer complex formation on the cloud-point of poly(JV-isopropylacrylamide) (PNIPAAm) in the poly(NIPAAm-co-acrylic acid) polyelectrolyte complex between poly(acrylic acid) and poly(ally-lamine), Polym., 1997, 38, 2759. 

Increases in the levels of water swell of the PVA hydrogels were initially presumed to be possible according to the mechanism commonly followed by covalently cross-linked hydrogels, namely, the incorporation of monomer components with exceptional affinities for water (typically, charged species such as carboxylic acid functional monomers). Thus, copolymers of VTFA and maleic anhydride were prepared, which when solvolyzed in methanolic ammonium hydroxide, would be expected to give poly [(vinyl alcohol)-co-(maleic acid)] products. Film samples of such copolymer hydrogels were prepared, and surprising sensitivity of water swell to acidic comonomer content was observed (Table IV). 

Worthy of special mention are copolymerizations involving acid comonomers, such as acrylic acid, methacrylic acid and itaconic acid. These monomers are... 

Storage Heat-sensitive refrigerate protect from iight Uses Vise, controi agent chemicai intermediates acryiic acid comonomer prod, of poiymers and copoiymers base materiai for paint, ieather, paper, and textiies dentai compds. adhesives floor care prods. oii additives toner resins food pkg. 

Hydroxyethyl acrylate, Itaconic acid comonomer, reactive S/B resins 2-Hydroxyelhyl methacrylate comonomer, reactive vinyl acetate 2-Hydroxyethyl acrvlate comonomer, refinisning paints Mhoromer AM 414 Mhoromer AM 438 comonomer, specialty coatings 1,4-Cycbhexanedlmethanol dMnyl ether, Cycbhexyl i/lnyl ether, 2-Ethythexyl i/lnyl ether Hydroxyhutyl vinyl ether, Rapl-Cure CHVE Rapl-Cure CVE Rapl-Cure DDVE Rapl-Cure DVE-2 Rapl-Cure DVE-3 Rapl-Cure EHVE Rapl-Cure HBVE Rapl-Cure PEPC comonomer, styrene polymerization Velsicol DOM... 

Isotridecyl methacrylate polymethacrylic acid comonomer Acrylic acid... 

A fast, direct and non-destructive method involving no sample preparation was developed for recording a well-resolved and reproducible spectmm of special acrylic fibre (SAF), a precursor for carbon fibre using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. A novel method was developed for determining the composition of SAF containing both acrylate and carboxylic acid comonomers. The special feature is that no standard samples (of known composition) are required. 11 refs. 

ABA 4-acetoxybenzoic acid, Comonomer 3-benzoyl-4-acetoxybenzoic acid. 

Textile products are also finally bleached and then dyed. Physical and/or chemical processes participate in dying processes and discussion of these is more a domain for textile chemistry. Here, the dyeability of synthetic fibers can be increased by polymerizing in small quantities of certain comonomers which have a better affinity to the dyestuffs than the monomeric units of the actual fiber forming polymer. For example, certain acidic comonomers I and II in PET and PA for basic dyestuffs, basic comonomer III in PET and PA for acidic dyestuffs, acidic comonomers IV-VI in PAN for basic dyestuffs, and basic comonomers VII-IX in PAN for acidic dyestuffs ... 

PCCE Polycyclohexylene dimethylene cyclohexanedicarboxylate, glycol and acid comonomer... 

Too much acid comonomer would ensure a safe oxidation reaction, but the reaction could become too slow to be commercially viable. If, however, too little is added, this would establish a higher onset temperature and the oxidation reaction would be likely to be too fast and uncontrollable. 

Acid comonomers can initiate the cyclization reaction of the nitrile groups ... 

Acrylic, methacrylic and itaconic acids also act as plasticizers, so it should not be necessary to add any additional plasticizer comonomer such as MA. However, for textile tow precursor, it may be necessary to introduce either more of the acid comonomer, or add some plasticizer monomer to facilitate the introduction of crimp, which aids packaging of the textile tow. 

Amide comonomers have a less pronounced effect than acid comonomers. Acrylate comonomers do not initiate the cyclization reaction [78,79], whilst MMA results in a lower carbon yield than MA. The bulky side groups of an ester comonomer lower the crystallinity and crystal size but improve the segmental mobility of the polymer chains [22,23]. The size of the ester molecule also affects the structural parameters of the precursor and the resultant carbon fibers have a lower average orientation and mechanical properties [21]. 

Polyvinyl alcohol is copolymerized with cross-linkable comonomers N-methylol acrylamide is self-curing. Carboxylic acid comonomers are cured by epoxy, urea, or phenolic resins. 

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