Blend studies amides

Like PU TPE, blends of thermoplastic polyurethanes and polyamide-12 (PA-12) have been studied by Polosmak and co-workers [61]. They have mixed two types of thermoplastic polyurethane (TPU) based on oligoether (polytetramethylene oxide, molecular weight, 1000) and oligoester (polyethylene butylene glycol adipate, molecular weight, 2000) and PA 12 were characterised by IR spectra and thermal analysis. IR spectra of TPU, PA-12 and their blends show that in amide one (Al) carbonyl absorbancy is seen to split [55] into two main bands with maxima at 1705 and 1730 cm 1. At 1730 cm 1,... 

In addition to comonomers, nylons are frequently used in blends. The pyrolysis of blends typically shows little interaction between the compounds generated from the individual blend components. However, a study on the co-pyrolysis of several polyamides in the presence of PVC showed interactions [40]. The study was done on nylon-12, nylon-6,6 and poly(1,4-phenylene terephthalamide) (Kevlar) in the presence of poly(vinyl chloride). Polyamide-PVC mixtures (typical mass ratio 1 1) were pyrolyzed at 700 and 900°C. It was found that the presence of PVC promoted the hydrol ic decomposition routes of amide groups and volatile nitrile formation from all examined polyamides due to the hydrogen chloride eliminated from PVC under pyrolysis. In the presence of PVC, an elevated yield of alkenenitriles was observed from nylon-12. For Kevlar in the presence of PVC, it was noticed the evolution of benzeneamine, benzoic acid, benzenenitrile and benzeneisocyanate. At 900°C in the presence of PVC, an enhanced evolution of HCN from nylon-12 and nylon-6,6 was noticed. 

EM and EMA-salts can also be used to improve the mechanical properties of Incompatible blends (3-14). The role of the EMA or EMA-salt In these systems Is not fully understood. In a recent publication, we have studied the polyethylene/EMA-salt/PA system by looking at the two binary systems from which it is made PE/EMA-salt and EMA-salt/PA (17). Concerning the EMA-salt/PA system, it has been suggested that an amidation reaction can occur between the NHj terminal groups of the PA and the COOH groups of the EMA, in addition to possible hydrogen bonding (5). However, very little work has been carried out in order to detect interactions in the PE/EMA-salt system. 

Dimethylol-5,5-dimethylhydantoin (DMDMH) and 3-methylol-2,2,5,5-tetramethylimidazolidinone (MTMIO) were mixed in different ratios in textile finishing systems for cellulose fabrics. The mixtures of 2,2,5,5-tetrame thylimidazolidinone (TMIO) and hydantoin rings on the grafted cellulose provided a combination of imide, amide and amine halamine stmctuies in different ratios after chlorination. These combinations improved both the power and stability of the biocidal properties of the treated cotton and polyester/cotton blend fabrics studied. Repeated laundering tests showed that even a small amount of added amine halamines could substantially reduce the loss of active chlorine and increase the power of the biocidal functions on the fabrics. The results were discussed. 12 refs. 

Double-tailed ester-type surfactants 6a-c, f, g and uronamides 10c, f, g were studied as to their properties as emulsifying agents. Three systems were studied sunflower oil-water, paraffin oil (Marcol 82)-water, and capric/caprylic triglycerides (Oleon)-water. In order to determine the w/o or o/w type of emulsions formed in the presence of the surfactants, the drop-dilution method was used. To a small portion of the emulsicMi (surfactant/water/oil 5/47.5/47.5 in weight) placed oti a slide, a drop of water with a pin point is added and stirred slightly. If the water blends with the emulsion, it is an oil-in-water emulsion, but if oil blends with the outside phase it is a water-in-oil emulsion. As indicated in Table 5, ester-type and amide-type compounds 6a-c and 10c, based on C8 to C12 fatty alcohols and amines, are able to form o/w emulsions whereas surfactants 6f, g and lOf, g composed of stearic (Cl8) or oleic (C18 l) alkyl chains exhibit w/o emulsions. 

Additional polymer blends comprising PAEK s offering property combinations of potential utility include PSF [Robeson and Harris, 1986 Harris and Robeson, 1989] structurally different poly(aryl ketones) [Harris and Robeson, 1986], PAr [Robeson and Harris, 1992], poly(amide-imide) PAI [Harris and Gavula, 1992], PPS [Robeson, 1987], and other PI [Harris et al., 1992]. Mixtures of structurally different PAEK s were noted to be isomorphic within specific limits of ether/ketone ratios [Harris and Robeson, 1987]. Blends of polybenzimidazole, PBI and several commercial PI (Ultem 1000 and Matrimid 5218) have been studied in depth at the University of Massachusetts and found to be miscible. FTIR studies [Guerra et al., 1988 Kim et al., 1993], NMR studies [Grobelny et al., 1990], thermal, dielectric, and mechanical... 

The PIB macroinitiators can also initiate living anionic polymerization of a wide variety of functional monomers, such as vinyl pyridine, N,N-dimethylacryl-amide, and a variety of protected monomers, such as silylated 2-hydroxyethyl methacrylate. Polymerization studies with these monomers are in progress. The resulting products are potential new thermoplastic elastomers, dispersing agents, blending compounds, emulsifiers, non-ionic surfactants, biomaterials etc. 

E. Sharmin, M. S. Alam, R. K. Philip and S. Ahmad, Linseed amide diol/DGEBA epoxy blends for coating applications Preparation, characterization, ageing studies and coating properties . Prog Org Coat, 2010,67,170-9. 

Two types of environmentally friendly jute fibre reinforced green composites have been studied. These are based on Mesua ferrea L. seed oil-based poly(urethane ester) and poly(urethane amide) resin blends with commercially available partially butylated melamine-formaldehyde and epoxy resins by solution impregnation and hot-curing methods. The composites were cured at a temperature of about 130-140°C under a pressure of 35.5 kg cm for around 2 h.The physical, mechanical and chemical properties of the epoxy-modified polyurethane composites were better than those of the MF-modified composites. They also possessed excellent chemical resistance and hydrolytic stability in water, acid and salt solutions, making them useful for low load-bearing applications. 

These poly(amide-imide) materials were extensively studied in the 1980s in various aspects (e.g. synthesis and preparation of blends with other polymeric materials), [2, 88-96] demonstrating the increasing interest in these materials. More recently, water soluble polyamides and poly(amide-imide)s [97] as well as polyhydroxyimides [98] structurally analogous to those described in Fig. 4.18 have been reported. Additionally, photoactive polymers were prepared by the condensation of a maleopimaric adduct with azo-dye type diamines [99]. The levopimaric... 

Another study regarding biosourced PLA blends with different contents of poly(ethylene oxide-/)-amide-12) (PEBA) was investigated by Hanet /. [117]. The authors have found that the impact triggered not only the generation of fibrils... 

Differential scanning calorimetry was used to study the non-isothermal crystallization behavior of blends of poly(phenylene sulfide) (PPS) with the thermotropic liquid-crystalline copoly(ester amide) Vectra-B950 (VB) [126], The PPS crystallization temperature and the crystallization rate coefficient increased significantly when 2-50% VB was added. The Ozawa equation was shown to be valid for neat PPS as well as for the blends. The values of the Avrami exponents matched well against those determined previously using isothermal analysis, and they are independent of the concentration of VB. 

Thermal studies (DSC) indicate a very high moisture absorption rate for pure PAI-1. The amide linkage m PAI, as in case of polyamides, is known to be very moisture sensitive and undergoes hydrolysis and chain scission when in the melt state in the presence of moisture. PAI-2 does not indicate the same moisture absorption properties observed in PAI-1. Addition of only 10% LCP decreases the moisture absorption of the blend dramatically. The T of the pure components and the blends increases on heat treatment. The presence of LCP is seen to inhibit the imidization of PAI. The major fiictors affecting imidization are temperature, time and diffusion of the water of imidization through the molded part. The presence of LCP which has good barrier properties, inhibits the diffusion of the NMP solvent and water of imidization which in turn inhibits the reaction. The T transition for PAI in DSC... 

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