DMA results

DMA. Introduetion of a 5-methyl or 5-bromo group, to produce 5-methyl-2,4-DMA and 5-bromo-2,4-DMA, results in active agents, but they are not signifieantly more potent than 2,4-DMA itself. It seems that the methyl and bromo substituents are tolerated at the 5-position, but they do not produce the increase in activity seen in the 2,5-DMA series. 

Hexachlorobutadiene and its metabolites preferentially distribute to the kidney, liver, adipose deposits, and possibly the brain. Some hexachlorobutadiene metabolites inhibit mitochondrial metabolism and react with DMA, resulting in cell death or tumorigenesis. Hexachlorobutadiene metabolites are excreted in the urine and feces. There is limited degradation to carbon dioxide which is exhaled from the lungs. 

Fig. 24 DMA results for (a) control foam, (d) 10% soybean oil polyol, and (e) 30% soybean oil polyol. Reproduced from [164] by permission of Elsevier Press...

DMA) binds reversibly to Cjq. A similar effect was observed for 2,6-dimethoxy-anthracene [60], Use of, for example, a ten-fold excess of DMA results in an equilibrium between the various Cgg DMA adducts, with e,e,e-C5oDMA3 as the main component. Hence, synergetic combination of kinetic and thermodynamic control results in the generation of templates such as with incomplete... 

An interesting result with respect to applications obtained with the IPN hydrogels is that these are two- phase systems (two glass transition temperatures), with the hydrophilic domains behaving essentially like the pure hydrophilic component.6,7,9 Thus, the two basic functions of these IPN hydrogels with respect to applications, namely hydrophilicity and mechanical stability, are separately taken over by the two IPN components, the hydrophilic and hydrophobic domains, respectively. Figure 1 shows TSDC and DMA results for the water content dependence of the a relaxation (dynamic glass transition) of PHEA in sequential IPNS prepared from PHEA and poly(ethyl methacrylate) (PEMA) as the hydrophobic component.9 In these IPNs a porous PEMA network was prepared first, and PHEA was then polymerized in the pores. In addition to the... 

Hawker et al. prepared the 1-phenylethyl adduct of BPPN, i.e., 2,2,5-trime-thyl-3-(l-phenylethoxy)-4-phenyl-3-azahexane, (TMPAH, Fig. 13) and found that it was useful for the controlled homopolymerizations of St, nBA, acrylonitrile, and N,N-dimethylacrylamide [71]. For example, the homopolymerization of DMA resulted in polymers with Mn=4000-55,000 with Mw/Mn=l.15-1.21. TMPAH was also used to prepare random copolymers containing St or nBA and the above monomers, in addition to copolymers with MMA, acrylic acid, 2-hy-droxyethyl acrylate (HEA),and glycidyl acrylate. As with DEPN, it was necessary to add the free nitroxide to mediate the polymerization rate, but the resulting... 

A pSt macroinitiator of Mn=20,300 with Mw/Mn=1.15 was chain extended with DMA, resulting in a block copolymer with Mn=43,000 and an Mw/Mn=1.24 [85]. The authors did not present monomer conversion data or GPC traces, so no conclusion about the rate of the reaction or blocking efficiency can be drawn however, there was no indication in the text that the polymerization was uncontrolled, as was originally observed for the ATRP system [200]. 

Figure 4.2 shows the DMA results of a PP/talc (85/15) system represented in the standard way i.e. the log G and log G plotted as a function of the temperature. The loss shear modulus curve shows relaxation maxima at about 60°C (the crystalline phase [a] relaxation) and at about 0°C the amorphous phase glass-rubber [S] relaxation). Blending such a PP sample with a C2C3 rubber results in an extra (rubber) relaxation maximum at about -50°C. 

A. Alkylating agents. These dmgs attack nucleophilic sites on DMA, resulting in alkylation and cross-linking and thus inhibiting replication and transcription. Binding to RNA or protein moieties appears to contribute litde to cytotoxic effects. 

Figure 13 DMA results for poly(ethylene terephthalate) film measured in tension at the different frequencies shown. The measurements were performed isothermally in 5°C increments and the apparatus allowed to come to thermal equilibrium for 5 min before the sequence of measurements was performed...

In the TMA plot in Fig. 7 it is possible to note the interactive nature of the substrate on the curing of the PF adhesive. For example, the modulus of elasticity (MOE) increase curve shows two sections (and a two peak first derivative curve). This indicates formation of entanglement networks of the resin in wood which is not possible on noninteractive substrates such as glass as in Fig. 6. Of course DMA and TMA give equally good results when used on the same wood substrate [379,380]. The ABES technique is also linearly correlated with TMA and DMA results as has been demonstrated by the linear relationship that has been found for both MUF and tannin formaldehyde adhesives in the results of TMA and ABES [381]. 

Mechanical Properties Chen et al. [2007] smdied the dynamic mechanical properties of films prepared by the solution casting method of PHBHV reinforced with HAp. The results indicated that at 75°C the storage tensile modulus of the polymer matrix, E , almost doubled by incorporation of 30 wt% HAp. The decrease in tan S was attributed to the hindrance of polymeric segment mobility by the nanofiller. Polyamide-69 has been reinforced with up to 10 wt% HAp [Sender et al., 2007]. The DMA results have pointed out an enhancement of the mechanical properties as a function of HAp content up to 5 wt% above this limit they deteriorated, probably due to the HAp agglomeration. 

Typical DMA results 127] for two diffierent sanities of poiyethyleoe (a) linear polyethylaK (b) branched polyethylene. (With the peimisston of DuPont Analytical IrMrumcnts.)... 

On the basis of the Voigt model, the following equations can be derived from DMA results ... 

Figure 3.5 DMA results for the pure SMP and syntactic foam. The Tg regions were determined from the storage modulus curves. Source [41] Reproduced with permission from Elsevier...

Table 8.9 DMA results of cast elastomers from Baytec MS-242 ...

The y-transition is a broad relaxation in the temperature- or frequency-domain, interpreted as a localized crankshaft-like motion of the backbone of the chain. This interpretation of the DMA result [51] agrees well with the calorimetry. The calorimetric results were interpreted already in 1962 based on an energy estimation as a local relaxation of gauche conformations in the amorphous phase [53,54]. The broad increases in the heat capacity beyond the vibrational Cp of amorphous PE seen in Fig. 2.46 were interpreted as a gradual, local unfreezing of the gauche-trans equilibrium. 

Figure 9.29 DMA results of neat epoxy and its composites, (a) Storage modulus and (b) Loss factor (tan5). Reprinted from [3] with permission from Elsevier.

Fig. 3.3 DMA results of the pristine Naflon film, the Ni-doped MFR IPMC with applied magnetic field in parallel and perpendicular directions. The resulting storage modulus (a) loss modulus (b) and tan ) (c) in a frequency range from 0.01 to 100 Hz in tensile mode. Reprinted from [Park and Kim (2007)] with permission from Elsevier, Copyright 2007.

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