Polyamide polymers properties

Because of the capacity to tailor select polymer properties by varying the ratio of two or more components, copolymers have found significant commercial appHcation in several product areas. In fiber-spinning, ie, with copolymers such as nylon-6 in nylon-6,6 or the reverse, where the second component is present in low (<10%) concentration, as well as in other comonomers with nylon-6,6 or nylon-6, the copolymers are often used to control the effect of sphemUtes by decreasing their number and probably their size and the rate of crystallization (190). At higher ratios, the semicrystalline polyamides become optically clear, amorphous polymers which find appHcations in packaging and barrier resins markets (191). 

Cycloahphatic diamines react with dicarboxyUc acids or their chlorides, dianhydrides, diisocyanates and di- (or poly-)epoxides as comonomers to form high molecular weight polyamides, polyimides, polyureas, and epoxies. Polymer property dependence on diamine stmcture is greater in the linear amorphous thermoplastic polyamides and elastomeric polyureas than in the highly crosslinked thermo set epoxies (2—4). 

Even within a particular class of polymers made by step-growth polymerization, monomer composition can be varied to produce a wide range of polymer properties. For example, polyesters and polyamides can be low-Tg, amorphous materials or high-Tg, liquid crystalline materials depending on the monomer composition. 

Dissolution/reprecipitation processes were evaluated for the recycling of poly-epsilon-caprolactam (PA6) and polyhexamethyleneadipamide (PA66). The process involved solution of the polyamide in an appropriate solvent, precipitation by the addition of a non-solvent, and recovery of the polymer by washing and drying. Dimethylsulphoxide was used as the solvent for PA6, and formic acid for PA66, and methylethylketone was used as the non-solvent for both polymers. The recycled polymers were evaluated by determination of molecular weight, crystallinity and grain size. Excellent recoveries were achieved, with no deterioration in the polymer properties. 33 refs. 

PTT, with three methylene units in its glycol moiety, is called an odd-numbered polyester. It is often compared to the even-numbered polyesters such as PET and PBT for the odd-even effect on their properties. Although this effect is well established for many polycondensation polymers such as polyamides, where the number of methylene units in the chemical structures determines the extent of hydrogen bonding between neighboring chains and thus their polymer properties, neighboring chain interactions in polyesters are weak dispersive, dipole interactions. We have found that many PET, PTT and PBT properties do not follow the odd-even effect. While the PTT heat of fusion and glass transition temperature have values between those of PET and PBT, properties such as modulus... 

NYLON. [CAS 63428-83-1], ( VI I NO), Generic name for a family of polyamide polymers characterized by lire presence of llie amide group —CONH. By far the most important are nylon 66 (75% of U.S. consumption i and nylon 6 (25% of U.S. consumption). Except for slight difference in melting points, the properties of the two forms are almost identical, though their chemical derivations are quite different. Other types are nylons 4, 9, 11, and 12. 

A series of dibenzazocines was designed for application in the synthesis of homochiral polyamide polymers <1998TA3497>. Bis-oxo-tetrahydrodibenzazocines showed picomolar to nanomolar inhibition of 17/ -hydroxysteroid dehydrogenase of type 3 <2006BML1532>. Colchicine derivatives that contain the dibenzazocine moiety have been studied for their biological properties <2000BMC557>. 

One simple idea is that styrenic block copolymers are almost never used as a stand-alone 100% neat polymer for any application or use. We tend to think about polymers in terms of this plastic soda bottle is polyester, or this carpet fiber is polyamide, or this house siding is PVC, or this garbage bag film is polyethylene , fully understanding and meaning that virtually 100% of the named object is that polymer. Our brains usefully process the named polymer properties set (as neat polymer) into the desired and required property set for its application. Life is simple in the 100% world. It is intuitive, and what we seem to know makes sense, looking either way properties wise, to why this polymer is used for this application. 

There is also an alternative numbering system for synthetic polyamides. Polymers that could be made from amino acids are called nylon-.r, where x is the number of carbon atoms in the repeating unit. Thus, polycaprolactam (1-13) is nylon-6, while the polymer from m-aminoundecanoic acid is nylon-11. Nylons from diamines and dibasic acids are designated by two numbers, in which the first represents the number of carbons in the diamine chain and the second the number of carbons in the dibasic acid. Structure 1-6 is thus nylon-6,6. Nylon-6,6 and nylon-6 differ in repeating unit length and symmetry and their physical properties are not identical. 

Preparation and characterization of highly branched aromatic polymers, polyphenylenes, polyesters, polyethers, and polyamides, were reviewed. These polymers were prepared from condensation of AB -type monomers, which gave noncrosslinked, highly branched polymers. The polymer properties are vastly different compared to their linear analogs due to their resistance to chain entanglement and crystallization. 

Effect of thermostabilizers on the polymer properties was studied by different physicochemical methods. For example, in the work [260] method of DSS (differential spectroscopy) was used to define the effect of polyester-imide on thermo-physical properties of PETP. By this method it was found out that polyester-imide reduces PETP ability to crystallization. Methods of thermogravimetric analysis (TGA) and infrared spectroscopy in the nitrogen atmosphere were used in the work [261] to define thermal stability of the mixture of PETP and polyamide with the additive - modifier - polyethylene. It has been found that introduction of the additive decreases activation energy which positively tells on the ability of PETP to thermal destruction. 

Factors Affecting Polyamide OPV. In order to determine the polymer properties which affect polyamide permeation properties, the n-I series was studied in more detail. Figure 3 shows the... 

In contrast to the previously discussed cationic ROPs, the nucleophilicity of the cyclic imino ether monomers is much higher compared to the resulting poly(cyclic imino ether)s. This decrease in nucleophilicity is due to the isomerization of the imino ether moiety into an amide during the CROP as depicted in Scheme 8.25. As a result, the CROP of a wide range of cyclic imino ethers can be performed in a living manner since chain transfer to polymer side reactions are less likely to happen. Moreover, the R-group attached to the 2-position of the monomer determines the polyamide side chains and strongly influences the polymer properties. 

J. G. Dolden. Structure-property relationships in amorphous polyamides. Polymer, 17(10) 875-892, October 1976. 

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. 

D. Bera, B. Dasgupta, S. Chatterjee, S. Maji, S. Banerjee, Synthesis, characterization, and properties of semifluorinated organo-soluble new aromatic polyamides, Polym. Adv. Technol. 23 (1) (2012) 77-84. 

This methodology is quite general and can be utilized to prepare several types of polymers such as polyamides, polyimides, polyurethanes, polyethers etc. The polymer properties depend on the type of functional groups that link the polymer building blocks. Further modulation is achievable by varying the nature of the difimctional monomer within each class of polymers. It is not always necessary to condense two difunctional monomers. Some polymers such as polyethers are prepared by the oxidative coupling of the corresponding phenols. A few examples of polymers that can be prepared by the condensation reactions are shown in Fig. 1.2. 

Substances that have been used in this context include glass fiber (occasionally glass beads), carbon fiber, carbon nanotubes, carbon black, graphite, fuUerenes, graphite chemically modified clays and montmorillonites, silica, and mineral alumina. Other additions have been included in polymer formulations, including calcium carbonate, barium sulfate, and various miscellaneous agents, such as aluminum metal, oak husks, cocoa shells, basalt fiber, silicone, rubbery elastomers, and polyamide powders. The effects of such additions of polymer properties are discussed next. 

Table 3 contains reaction conditions and polymer properties for polybenzoxazoles prepared by one-step thermal polymerizations and by cyclization of the intermediate polyamides. The latter dehydration process was readily followed by IR. The polyamides have strong bands near 1655 cm which gradually disappear during the cyclization. Concomitant appearance of the characteristic benzoxazole band at 1600-1620 cm confirms the process and the product structure. In addition, microanalysis data have been obtained for the polybenzoxazoles from monomers and Calculated and found values for C, H, and N were within 0.3% of each other for the former. The values for the latter were consistent with either equivalent of bound H2O per repeat unit and/or incomplete cyclization. 

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