Monomeric acrylamide

Polyacrylamide is a cross-linked polymer of acrylamide. These gels are more difficult to prepare than agarose. Monomeric acrylamide (which is a known neurotoxin) is polymerized in the presence of free radicals to form polyacrylamide. The free radicals are provided by ammonium persulfate and stabilized by TEMED (/V/V/V/V -tetramethylethylenediamine). The chains of polyacrylamide are cross-linked by the addition of methylene-bisacrylamide to form a gel whose porosity is determined by the length of chains and the degree of cross-linking. The chain length is proportional to the acrylamide concentration usually between 3.5 and 20%. Cross-linking bis-acrylamide is usually added at the ratio 2 g bis/38 g acrylamide. 

Polyacrylamide gels are formed by polymerisation of monomeric acrylamide CH2=CH-CO-NH2... 

Immobilization of Glucose Oxidase. The enzyme glucose oxidase was incorporated into the aqueous phase of a cubic phase similar to that polymerized in the previous section, and this aqueous phase made polymerizable by the addition of monomeric acrylamide. Except for a slight yellowish color from the strongly-colored glucose oxidase, the result was an optically clear polymerized materiaL TTie concentration of... 

In these detection procedures, which are certainly not the most popular, but most accurate, the absorbancy of the supporting medium plays an important role. Thus, monomeric acrylamide has a UV absorption peak at 280 nm which decreases upon polymerization. Polyacrylamide gel has a rather low extinction coefficient below 270 nm, but absorption rises rapidly, and at 270 nm is characterized by the extinction coefficient, 0.569. Therefore unpolymerized acrylamide must be absent in the gel if spectrophotometric evaluation of the gel is to be applied. To ensure this Watkin and Miller [193] recommended to use only 0.2% Bis in 7.5% gel. 

Table 1. Peak potentials of different monomeric acrylamides, (1.5 X 10-3 M).

Anionic and non-ionic polyacrylamides (monomeric acrylamide content 0.05 So referenced to the polymer)... 

A series of experiments was conducted to verify the neutralization procedure used for wastes containing monomeric acrylamide. The procedure is based on the addition of sodium bisulfite to the carbon-carbon double bond o acrylamide In the presence of peroxide ... 

As discussed in Sect. 9.2, lAMS has been applied in the study of atmospheric processes. As such, lAMS can contribute to an understanding of acid rain, smog, and other air contamination processes in the atmosphere. Important additional tools in this respects are the aerosol mass spectrometer (Sect. 6.2) and the infrared image furnace (IIF, Sect. 6.4.3). The latter system was involved in studying combustion of polycarbonates, which may result in the emission of the endocrine disraptor bisphe-nol A. Li+-IAMS enabled the detection of the bisphenol A biradical [21]. Similarly, EGA-IAMS has been used to study the pyrolysis of polyacrylamide, which among others results in the suspected carcinogenic monomeric acrylamide [22]. 

Polyacrylamide, produced from monomeric acrylamide (2-propenamide), has been used for decades in various industrial processes, e.g., as a flocculant in the treatment of drinking water. Especially for reasons of occupational health and safety, numerous toxicological studies on acrylamide have already been conducted. These studies have shown above all that on high exposure, acrylamide (i) binds to hemoglobin in the blood, (ii) is metabolized to reactive epoxide glycidamide and (iii) is carcinogenic on chronic exposure in animal tests. For this reason, acrylamide was put about 20 years ago... 

Nishimura and Yamada [10-11] introduced a water-soluble polymeric support having a linker recognized by ceramide glycanase for a synthesis of ganghoside GM3 (17). Synthesis of the polymerizable lactose derivative (14) with a ceramide glycanase sensitive linker is shown in Scheme 10.3. The lactosyl ceramide (Lac-Ger) mimetic glycopolymer (15) is obtained from the monomeric precursor (14) by co-polymerization with acrylamide. 

More than a dozen biocompatible and biodegradable polymers have been described and studied for their potential use as carriers for therapeutic proteins (Table 13.5). However, some of the monomer building blocks such as acrylamide and its derivatives are neurotoxic. Incomplete polymerization or breakdown of the polymer may result in toxic monomer. Among the biopolymers, poly-lactide cofabricated with glycolide (PLG) is one of the most well studied and has been demonstrated to be both biocompatible and biodegradable [12]. PLG polymers are hydrolyzed in vivo and revert to the monomeric forms of glycolic and lactic acids, which are intermediates in the citric acid metabolic pathway. 

If both continuous and dispersed phases of highly concentrated emulsions contain monomeric species, it is possible to obtain hydrophilic/hydrophobic polymer composite materials. Polyacrylamide/polystyrene composites have been prepared in this manner [180], from both w/o and o/w HIPEs containing aqueous acrylamide and a solution of styrene in an organic solvent. 

I), other important alkaloids are used as amine reagents for Mannich synthesis. Thus, demethylatcd nicotine affords aminomethylation of hydrogen cyanide (460), employed in studies of the metabolic oxidation of nicotine, and anabasinc gives, by reaction with acrylamide, the readily polymerizable monomeric species 461, the polymeric derivative of which is. 50 times less toxic than the original anabasinc. ... 

Reaction of quaternary salt 226 with 4-melhylpiperidine gives rise to 4-(4-methylpiperidino)pyridine (277), which is a liquid, in contrast to the crystalline DMAP (228) and PPY (184) (83EUP74837). The reaction of 4-cyanopyridine (274) with acrylamide in the presence of HCI furnishes the crystalline quaternary salt 278, in quantitative yield, which is readily aminated with dimethylamine. Subsequent cleavage of the aminated quaternary salt by heating with strong alkali solution gives monomeric or... 

Figure 3. SDS-PAGE, on a 0.8% agarose, 3.5% acrylamide gel run in tris-glycine buffer, of samples after crosslinking with glutaraldehyde. Bands were stained with silver. Lane 1, M2S, mtase lane 2, MjS, mtase + R subunit lane 3, M,Si + M subunit lane 4, MiS, visible at very bottom of gel lane 5, M,S, + R subunit lane 6, M subunit + R subunit lane 7, M subunit dimer with the predominant M subunit monomer having migrated off the base of the gel lane 8, R subunit in a monomeric form.

To dissect the contributions of classical multivalent effects from the steric mechanism. White-sides and coworkers demonstrated that when monomeric sialic acid derivatives were added along with the acrylamide polymer, more efficient (on a molar sialic acid basis) inhibition of agglutination was observed [149,162,163]. Addition of the monomeric inhibitors is proposed to have two effects. First, displacement of a polymer-displayed ligand by monomer would lower the affinity of the polymer for the surface of the virus. Second, the size of the polymer not bound to the surface is necessarily increased, and thereby increases the ability of the polymer... 

Polymeric chemicals are a somewhat special case. These are most frequently introduced as direct additives as coagulant aids. By virtue of their function, these polymers are almost quantitatively removed from the water during normal treatment. Even if applied inappropriately, these chemicals are of such high molecular weight that they would not be absorbed and are almost certainly not a threat to health if they have been properly tested. A potential difficulty with these chemicals is that they may contain varying amounts of the monomers used in their synthesis or other incompletely reacted material of lower molecular weight. Some of the monomeric compounds are quite toxic. Acrylamide is an example of one of these compounds that is neurotoxic. 

Cationic vesicles typically used for DNA delivery often self-aggregate or bind to plasma proteins in vivo. Wu et al. [104] attempted to improve vesicle stability using a cationic lipid with a cross-linkable acrylamide attached to the headgroup (Fig. 16). Vesicles were polymerized using thermal initiation with AAPD. Compared to monomeric vesicles, polymerized vesicles were less cytotoxic, more resistant to aggregation in serum, and comparable in transfection activity using a vector encoding firefly luciferase. 

U.S. 6506372 (2003) Dubief et al. (L Oreal) Amphoteric polymer with at least one monomeric unit from (meth)acrylate or (meth)acrylamide having at least one fatty chain (C8-C30) Improved disentanglement and softness... 

Safety concerns for synthetic polymers are sometimes due to contamination with monomeric impurity. Monomers are sometimes highly toxic (e.g., acrylamide [94]) or even carcinogenic (e.g., ethyleneimine [95] or vinyl chloride [96]) or highly irritating to skin (e.g., acrylamide [94] or acrylic acid [97]).Therefore, control of unreacted monomer level can sometimes be critical to the safety performance of synthetic polymers. 

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