Polyamide preparation

Miscellaneous Applications. Polyamides, prepared from polyamines and neodecanoic acid, are used as wash-cycle antistatic agents (qv)... 

Photosensitive functions are in many cases also heat sensitive, so the preparation of photosensitive polyimides needs smooth conditions for the condensations and imidization reactions. Some chemical reactants, which can be used for polyamide preparation, have been patented for the synthesis of polyimides and polyimide precursors. For example, chemical imidization takes place at room temperature by using phosphonic derivative of a thiabenzothiazoline.102 A mixture of N -hydroxybenzotriazole and dicyclohexylcarbodiimide allows the room temperature condensation of diacid di(photosensitive) ester with a diamine.103 Dimethyl-2-chloro-imidazolinium chloride (Fig. 5.25) has been patented for the cyclization of a maleamic acid in toluene at 90°C.104 The chemistry of imidazolide has been recently investigated for the synthesis of polyimide precursor.105 As shown in Fig. 5.26, a secondary amine reacts with a dianhydride giving meta- and para-diamide diacid. The carbonyldiimidazole... 

Another transition appeared at about 130 °C on the rescanning after rapid cooling of the molten sample. It seems to be a glass transition point. The polyamide prepared in bulk at 70 °C also melted sharply at 250—260 °C. On the other hand, the crosslinked polymer, which was prepared in bulk at 100 °C in a high conversion, has nothing but a broad endothermic curve up to near 300 °C as shown in Fig. 9. 

While allowing rapid preparation of a range of polyamides, these resins install a T,A-selective y9-Ala residue at the C-terminus, which places Hmits on the DNA sites that can be targeted ]46]. The shortest tail available from these resins is a propanolamide, obtained by reductive cleavage. Polyamides prepared on Boc-Gly-PAM resin can be reductively cleaved to obtain ethanolamide tails, but it was expected that further truncation of the C-terminus would be necessary for tolerance... 

Photodissociation of the polyamides (Figures 4 and 5) was carried out in the solid films. Polymer films (1-2 U m) were cast onto quartz substrates and were exposed to monochromatic 250 nm light from a spectroirradiator. The dissociation of the thymine photodimers was followed by monitoring the absorbance at 270 nm. The results obtained for the polyamide prepared from the reaction of propane diamine and the isomers of the thymine photodimer (cis-syn(17a), cis-anti(17b), and... 

However, only (a) and (b) are constitutional repeating units, describing the polymer s constitution precisely and completely. The polyamide prepared from hex-amethylenediamine and adipic acid has the following constitutional repeating unit ... 

In order to illustrate this problem, it is interesting to analize the unsubstituted polyamides prepared from aliphatic diamines and aromatic diacids or from aliphatic diamines and aliphatic diacids. They are only soluble in solvents such as sulphuric acid, trifluoracetic acid, m-cresol, etc. 

J.H. Fabris, Novel poly(urethane-amide)s from polyurethane prepolymer and reactive polyamide. Preparation and Properties. Adv. Urethane Sci. Technol., 4, 89-111 (1976). 

Jikei, M., and Kakimoto, M. A. 2001. Hyperbranched aromatic polyamides prepared by direct polycondensation. High Perform. Polym., 13, S33-S43. 

NH(CH2)6NHOC(CH2)4CO]n-, a synthetic polyamide prepared by the two step polycondensation of hexa-methylenediamine and adipic acid. 

Polyamides prepared by cationic polymerization of lactams contain a significant fraction of cyclic oligomers. Reactions leading to formation... 

Nylon-6,6, discovered by Carothers in 1929, is by far the most important polyamide prepared by condensation polymerization. Nylon 6, prepared by the ring-opening (non-condensation) polymerization of e-caprolactam, will not be discussed in this chapter. Other commercially important polyamides prepared by condensation techniques include nylon-6,10, from hexamethylene diamine and sebacic acid, poly(/n-... 

The chemistry of synthetic jasmine materials was given an enormous boost in the 1930s when Nylon 66 was launched as a product. Nylon 66 is a polyamide prepared using adipoyl chloride and hexamethylenetetramine as monomers. The 66 in the name refers to the fact that there are 6 carbons in each type of unit that lies between the amide links in the polymer chain. Thus, adipic acid is the key feedstock for Nylon 66 and the introduction of the latter meant that the former became a basic chemical commodity. Pyrolysis of the calcium or barium salt of adipic acid produces cyclopentanone, and so the availability of large quantities of the acid meant that the ketone could also be prepared at low cost. 

The structure of an amorphous polyamide prepared from hexamethylenediamine and isophthalic/tere-phthalic acids was modified in order to determine the effect of chemical structure on the oxygen permeation properties. The greatest increase in permeation was obtained by lengthening the aliphatic chain. Placement of substituents on the polymer chain also led to increased permeation. Reversal of the amide linkage direction had no effect on the permeation properties. Free volume calculations and dielectric relaxation studies indicate that free volume is probably the dominant factor in determining the permeation properties of these polymers. 

Other condensation polymers as polyamides should also be mentioned. For polyamides prepared by hydrolytic polymerization, the rate of thermooxidation is highly influenced by the content and ratio of carboxylic and amino end groups. In the case of polyamides with only carboxylic end groups, loss of molecular weight is... 

When unsymmetrical monomers are used, the normal ability of the polymer to crystallize can be disrupted amorphous (transparent) nylons can then be formed. For example, the polyamide prepared from the condensation of terephthalic acid with a mixture of 2,2,4- and... 

Thermoplastics are aromatic polyamide prepared by polymerization of aromatic diamine and aromatic diacid or its derivatives (e.g., anhydride). These plastics are characterized by high heat re-... 

Nomex is an aramid fiber used for fire-resistant protective clothing. It is a polyamide prepared by condensation of 1,3-benzenediamine (m-phenylenediamine) and 1,3-benzenedicarboxylic acid (isophthalic acid). What is the repeating unit of Nomex ... 

In this section we discuss not only wholly aromatic polyamides, but also some mixed polyamides, prepared from aromatic diacids and aliphatic diamines, or vice versa. One such material was already described in Section 6.3.2. Another one, called Nylon 6T, is formed by interfacial polymerization of terephthaloyl chloride and hexamethylenediamine ... 

Key words vegetable oil-based addition polymers and polyamides, preparation of addition polymers and polyamides, structure-property relationships of addition polymers and polyamides, application of addition polymers and polyamides. 

The study of polyamides prepared from vegetable oils is an old field of research which has not reported any new data in the last three decades. Polyamides from TO and SOYO wctc used mainly in the paint industry because... 

Garcia-Martin M.G., Ruiz Perez R., Benito Hernandez E., Galbis J.A., Synthesis of L-arabinitol and xyhtol monomers for the preparation of polyamides. Preparation of an L-arabinitol-based polyamide, Carbohyd. Res., 333, 2001, 95-103. 

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