Diamine monomer

Copolymers. There are two forms of copolymers, block and random. A nylon block copolymer can be made by combining two or more homopolymers in the melt, by reaction of a preformed polymer with diacid or diamine monomer by reaction of a complex molecule, eg, a bisoxazolone, with a diamine to produce a wide range of multiple amide sequences along the chain and by reaction of a diisocyanate and a dicarboxybc acid (193). In all routes, the composition of the melt is a function of temperature and more so of time. Two homopolyamides in a moisture-equiUbrated molten state undergo amide interchange where amine ends react with the amide groups. 

Conditions for low temperature solution polymerizations of pyromellitic dianhydride (PMDA) have been developed for a wide variety of aromatic 1,4-phenylene [54, 55] and 4,4 -biphenylene [56-58] diamine monomers in a number of aprotic solvents to give high molecular weight prepolymers referred to as polyamic acids. Since the imidized structures are insoluble, they must be processed in the form of their polyamic acids which are subsequently imidized thermally or by chemical dehydrating agents. Although this procedure is acceptable for thin film or fibers, the fabrication of thick parts is complicated by the water of imidization. 

ODA). These polymers are characterized by excellent high temperature properties with Tgs typically above 270 °C and continuous service temperatures of about 230 °C. The PAIs utilized here for blending studies were prepared by a simple solution polymerization route, i.e., by reacting trimellitic anhydride acid chloride and 6FDA and diamine monomer (ODA and MDA) in an appropriate solvent (e.g., DM Ac). 

Fluorine-Containing Aromatic Diamines - Monomers for High Performance Polymers ... 

However, similar structures were observed with etched surfaces of amorphous linear thermoplastics, such as polystyrene and poly(methyl methacrylate). Moreover, the small-angle X-ray scattering (SAXS) spectra of simple epoxy networks based on diepoxy and diamine monomers were... 

Recent adaptations of this technology provide structurally sound shellwalls that can be varied to release in a controlled manner [5]. Conventional methods to alter release fh)m microcapsules include using less monomer and making smaller microcapsules. However, processing in this way to control shellwall thickness could lead to fragile microcapsules. Controlled release with more robust microcapsules was achieved by using specified ratios of unique diisocyanate and triisocyanate monomers dissolved in the pesticide. Diamine monomers added to the emulsion in the typical manner produced robust microcapsules with desired rates of release. 

In contrast, the chiral 1,2-diamine monomer was copolymerized with styrene to produce 184 (Scheme 3.58) [119]. As the chiral monomer possessed two polymerizable groups, the crosslinking polymers were obtained via a copolymerization. This flexible crosslinking structure, when compared to DVB crosslinkage, gave 184 with high reactivity and satisfactory enantioselectivities in the asymmetric hydrogena-... 

Imai et al. [52-54] used the following highly phenylated heterocyclic systems as diamine monomers 2,5-bis(4-aminophenyl)-3,4-diphenylthiophene 35, 3,4-bis(4-amino-phenyl)-2,5-diphenylfuran 36, and 3,4-bis(4-aminophenyl)-2,5-diphenylpyrrole 37. 

Polyamides are commonly named as Nylon followed by two numbers, in which the first one denotes the number of carbon atoms in the diamine monomer and the second one refers to the number of carbon atoms in the diacid monomer. If a cycle is part of the polyamide, either in the amine or the acid moiety, the first letter of the cycle name must be used. In addition, if the polyamide is derived from an amino acid, only one number has to be used that describes the number of carbon atoms between the two functionalities. These rules are shown in Table 3.3. 

Generally, PAs are produced by the dehydrating polycondensation of a diamine monomer and a dicarboxylic acid monomer. 

Partially aromatic polyamides consist of aromatic dicarboxylic acid and aliphatic diamine monomer units. Such polyamides are generally characterized by high melting points, high glass transition temperatures, low moisture absorption and, unlike aliphatic polyamides such as nylon 6 and nylon 66, good dimensional stability under moist conditions. 

The diamine is synthesized by coupling 2,2 -dimethylbiphenyl-4,4 -diol with p-chloronitrobenzene. Subsequently, the nitro groups are re-dueed. For similar reasons, 3,3, 5,5 -tetramethyl-2,2-bis(4-(4-amino-phen-oxy)phenyl)propane has been introduced as a diamine monomer. Poly-... 

When highly basic diamines, are used, e.g., aUcycUc diamines are used as a diamine monomer, a salt is produced by the neutralization reaction before forming a poly(amic acid) at the point that the ahcyclic diamines are mixed with acid dianhydrides and precipitated. Since this salt is in a stable state, it is neither possible to form a poly(amic acid) by polymerization reaction nor to imidize poly(amic acid) by the reaction with a hydrating reagent. ... 

Films of poly(amic acid) and PI can be deposited by CVD. The dianhydride and diamine monomers are co-evaporated. The process is completely dry in nature. The rate of vaporization must be controlled to provide proper stoichiometric amounts of material to be deposited. ... 

Ratios of the amine/epoxy equivalents in different phases are shown in Fig. 25. Now, due to its semipermeable character, the P-phase retains the excess diamine monomer segregated at low conversions, leading to a significant departure from stoichiometry. However, the effect on the a-phase (amine defect) is not so significant because of its high volume fraction in the system. 

As shown in Table 13.7, the free energy of reaction of aramid polymerizations is reported to be negative even with aromatic acid, ester, and diamine monomers. In spite of this driving force, the rate of reaction is extremely slow because of the high activation energy of the polymerization reaction [51]. 

Figure 2. Diamine monomers for the generation of NLO tethered polyimides.

This same synthetic approach was also used to create diamine ROMP monomers. The homopolymers were again selective for S. aureus, but not for E. coli. Since the diamine monomers closely resembled the methyl monomers in terms of hydrophobicity, copolymers of these two monomers were... 

Synthesis of N,N,-bis(4-aminohenyl)-N, N -bis[4-(2-phenyl-2-isopropyl) phenyl]- ,4-phenylene-diamine (4). The dinitro compound (3) (5 g, 6.77 mmol ), Pd/C (0.2 g), and 150 ml ethanol were taken in a three-necked ttsk and hydrazine monohydrate (10 ml) was added drop wise over a period of 30 min at 90°C. Upon completing the addition, the solution was stirred at re Dux temperature for 12 hr. After the solution was cooled down to room temperature, the solution was Eltered to remove the catalyst, and the crade product was puriCbd by silica gel column chromatography ( -hexane ethyl acetate = 2 1) to afford diamine monomer (4) 2.3 g fyield 50%), mp 149-15 PC by DSC (10°C/min). 

Reversible bond formation can, in principle, be used for the selfcorrection of product structures. For example, the formation of Schiff bases, boroxines and boronates has been applied to on-surface polymerizations, but has so far met with limited success. Linderoth and Gothelf employed trialdehyde 62 and diamine monomers 63 towards 2-D polymer synthesis on Au(lll) under UHV (Figure 28.28a) [134], but unfortunately obtained only branched or irregularly networked stmctures, a situation that was ascribed to the flexible monomer structure employed. In addition, UHV conditions caused an irreversible loss of water, the presence of which was essential to bring about the back-reaction. When Abel and coworkers synthesized boroxine/boronate networks on Ag(lll) under UHV [135] they were unable to achieve the expected periodic order this contrasted with the findings of Yaghi et al., who employed the solution approach (see Section 28.5.2). This difference was most hkely a consequence of irreversible bond formation. 

Several aspects of this research are particularly exciting. The condensation polymerization method allows for preparation of a broad spectrum of polymers with different primary structures based simply on using different diacid and diamine monomers. As a result, by choice of the acid and diamine monomers, one can alter, in somewhat predictive fashion, such polymer properties as melting point, solvent solubility, crystallinity, film and adhesive characteristics and undoubtedly other polymer properties that remain to be studied. Furthermore, the condensations require no aldaric acid hydroxyl group protection/deprotection, a very important cost consideration in the potential production of any of these materials. 

Figure 9.14 Diamine monomer for a fluorescent light-emitting polymer [77],...

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