Cycloaliphatic polyamine

NIPU networks are created by the reaction between polycyclic carbonate oligomers and aliphatic or cycloaliphatic polyamines with primary amino groups [4], This forms a cross-linked polymer with p-hydroxy urethane groups of a different structure—polyhydroxyurethane polymer. Since NIPU is obtained without using highly toxic isocyanates, the process of synthesis is relatively safe for both humans and the environment in comparison to the production of conventional polyurethanes. Moreover, NIPU is not sensitive to moisture in the surrounding environment. 

Nonetheless, for the more than 50 years since the first publication in this field, NIPUs still do not have sufficiently broad application. This can be explained by certain features of these materials. Cyclic carbonate (CC) groups interact with aliphatic and cycloaliphatic polyamines at ambient temperatures more slowly than isocyanates with hydroxyl groups. The rate of this reaction is comparable to the rate of curing epoxy resins (ER) with amines. At the same time, the CCs react only with primary amino groups, in contrast to the ERs, which react with primary and with secondary amino groups. This results in a decrease in cross-linking density of the polymer network. 

Cycloaliphatic polyamines are less reactive than aliphatic amines, and an accelerator must therefore be used for curing at room temperature (e.g., salicylic acid). Aromatic polyamines are even less reactive than cycloaliphatic amines. Therefore, accelerators must be used to cure aromatic amines with epoxy resins at room temperature [2.125]. 

Epichlorohydrin has also been condensed with aromatic and cycloaliphatic polyamines to give resins which can be cured to products with high heat distortion temperatures and low moisture pickup. 1,3,5-Tris(aminomethyl)benzene (20) and cyclohexane (21)/epichlorohydrin condensates have been reported which can be cured to products with heat distortion temperatures in excess of 200°C and with good adhesion. " Poly-... 

Isophorone diamine (IPDA), bis(4-aminocyclohexyl)methane (PACM), and 1,2-diaminocyclohexane (1,2-DACH) are the principal commercial cycloaliphatic polyamine curing agents. IPDA is the largest volume cycloaliphatic amine. Commercial cycloaliphatic amines are formulated products. In addition to the cycloaliphatic amines, other components such as aliphatic amines and plasticizers are also included to improve RT cure speed and end-use properties. One popular formulation consists of IPDA used in combination with trimethylhexamethylene-diamines (TMDA) or meta-xylenediamine (MXDA), and plasticizers/accelerators such as nonyl phenol or benzyl alcohol. In some ambient cin-e coating applications, cycloaliphatic amines can be reacted with phenol and formaldehyde to form the Mannich base products, which have an internal phenol accelerator and cure readily at ambient temperatin-es. 

A modified cycloaliphatic polyamine curing agent for epoxy resins for filament winding. 

A modified cycloaliphatic polyamine curing agent for epoxy laminating and casting resins. Features include resistance to water spotting, good low temperature cure and chemical resistance. 

Fuel additives - [AMNES-CYCLOALIPHATIC AMINES] (Vol 2) - [SULFONIC ACIDS] (Vol 23) -arsenic compds as [ARSENIC COMPOUNDS] (Vol 3) -boron compds as [BORON COMPOUNDS - BORIC ACID ESTERS] (Vol 4) -coordination compounds as [COORDINATION COMPOUNDS] (Vol 7) -ethers m [ETHERS] (Vol 9) -magnesium alkyls as [MAGNESIUM COMPOUNDS] (Vol 15) -polyamines as [DIAMINES AND HIGHER AMINES ALIPHATIC] (Vol 8) -htanates as [TITANIUM COMPOUNDS - ORGANIC] (Vol 24) -use of copper compounds [COPPER COMPOUNDS] (Vol 7)... 

Cycloaliphatic and polycyloaliphatic polyamines are finding increasing use as non-toxic replacements. Polycycloaliphatics have shown outstanding mechanical properties, high acid and solvent resistance and similar adhesion compared with standard plasticised aromatic amines (Hunt and Ashcroft, 1994). 

Another group of curing agents based upon the polyamine concept is the cycloaliphatic amines. These have properties somewhere between those of the aliphatic amines and the aromatic amines. Typical examples are aminoethyl piperazine and methane diamine... 

The hardeners for cold-setting systems include aliphatic and cycloaliphatic amines and polyamines, adducts of polyamines and epoxy resins, phenol-amine combinations, and condensates of polyamines and dimerized fatty acids (polyaminoamides). Whereas amine hardeners must be used in a stoichiometric ratio to the reactive epoxy groups, polyaminoamides may be overdosed to a certain extent and thus used to elasticize the adhesive resin. 

Examples of catalysts are shown on the first line, whereas all the other compounds are coreactants including dicyandiamide, ureas, imidazoles, aliphatic polyamines, cycloaliphatic polyamides, and cycloaliphatic dicarboxylic acid anhydrides. As all the corresponding reaction mechanisms have been previously disclosed in detail," the following presentation is limited to the initial reaction steps leading to the active species involved in the polymerization or polycondensation processes. These primary attacks are enlightened in Fig. 12.6, which displays only one epoxy group reacting with catalysts or coreactants. 

---