Physicomechanical properties

The optimum molecular mass (Mw) of these copolymers containing 1,5-2% of monomeric units of 7, amounts to 47000—55 000 which makes it possible to obtain concentrated (15—17%) solutions with sufficiently high stability and to spin fibres with high physicomechanical properties (P = 36—40 gf/tex, (4—4,4 g/denie),... 

Poly (iminocarbonates) are little known polymers that, in a formal sense, are derived from polycarbonates by the replacement of the carbonyl oxygen by an imino group (Fig. 5). This backbone modification dramatically increases the hydrolytic lability of the backbone, without appreciably affecting the physicomechanical properties of the polymer the mechanical strength and toughness of thin,... 

Physicomechanical properties of the samples using both methods (strength of stretching and dividing) change about 3-4 % which is within the limits of permissible effect. 

Testing separately samples using both methods at 100°C learns that that the velocity of the processes increases considerably and the time for treatment is shortened but the values of physicomechanical properties are reduced with 8-9%. That is a reason to consider that optimal conditions for treatment using both methods are 80°C during 50 minutes. These conditions could be created and maintained in means for decontamination and disinfection of devices and armament. 

Optimal conditions for treatment of the coatings are specified -temperature 80°C, time for treatment - 50 min. Physicomechanical properties of garment are reduced after having been treating three times with 3-4%, which is within the limits of permissible influence.in the Republic of Bulgaria in accepted means for decontamination and disinfection of devices and armament. 

Heterophasic propylene copolymers, physicomechanical properties of, 26 539t... 

Engelberg, I. and Kohn, J. (1991). Physicomechanical properties of degradable polymers used in medical alications—a comparative study. Biomaterials, 12, 292-304. 

However, some excipients have multiple functions. For example, microcrystalline cellulose can function as a filler, a binder, and a disintegrant. As seen in Table 7.3, a typical low-dose formulation could include more than 85% filler—binders. Thus, physical and chemical properties for these specialty excipients are extremely important in a low-dose formulation for manufacturability, product performance, and longterm stability. Because the poor physicomechanical properties of components are not altered during manufacture as they are in the wet or dry granulation process, critical material properties and their impact on product quality attributes should be well characterized and understood.23 Discussion in this section will focus on fillers-binders. For those requiring more information on excipients, several excellent books and review articles are available in the literature.24-27... 

Chitin was evaluated as a direct-compression vehicle using powder flow properties and the physicomechanical properties of the manufactured tablets, and it was proven that this natural polymer has suitable characteristics for being used for this end. 

Theoretical premises for the determination of the physicomechanical properties by the acoustic pulse method were derived from the following three models of real foam structures... 

Kranz H, Ubrich N, Maincent P et al. Physicomechanical properties of biodegradable poly (D, L-lactide) and poly(D, L-lactide-co-glycoIide) films in the dry and wet states. J Pharm Sci 2000 89 1558-66. 

At an early stage during the preformulation program for the candidate, particularly for those with unfavorable physicochemical and physicomechanical properties as a free acid or free base, it is normal procedure to investigate a suitable range of potential salts. Typically 4-6 different salts are evaluated, if they can be isolated. Often the properties of the free acid (or free base) are hardly satisfactory and it is recommended that it is included in the comparative exercise using a battery of tests (see Section V). If a parenteral dosage form is intended and the properties of the free acid or free base are better than any of the salts, it is often possible to prepare a salt in situ in the liquid vehicle. 

Processes of mechanical and dielectrical relaxation as well as structural-morphological self-organization in these systems under vibrowave treatment have been already described in our previous work [8]. In the presented work the major attention is paid to an estimation of elastic-strenght properties of latex films and their IR-spectra. Figures 1 and 2 illustrate the dependence of physicomechanical properties of films on their composition, and also change of these dependences at simple mechanical influence (stirring of a latex by means of a mechanical stirrer) and under vibrowave treatment. 

Preliminary tests on search of optimum conditions of vibrowave stirring for obtaining mixtures with improved physicomechanical properties have shown that from three varied factors (ratio of latexes in a mixture, frequency and time of vibrowave treatment) crucial factor is a composition of mixtures. 

Curves structure vs. physicomechanical property (break stress and relative elongation at the moment of break) for films made from latex treated by nonlinear vibrations demonstrate a deviation from the additive dependence in the form of an extremum which corresponds to mixtures with the dominating content of relatively more hard-chain polymer, which relaxation characteristics cause its greater sensitivity to vibrowave treatment (Figure 1,2). 

It is obvious, that correlation of anisotropy of structure and physicomechanical parameters of properties is most pronouced in the presence of anisodiametric morphological formations. Comparison of physicomechanical properties of films obtained from latex treated by vibrowave action and in solid-phase mixturing of the same polymers, where defining criteria are stress and deformations of a shift, allows to prove the efficiency of vibrowave influence. 

The wave effects concerning the organization of a controlled tubulization in a resonance regime in multiphase systems, three-dimensional current and deagglomeration of associates, lead to obtaining dispersions with narrower particle size distribution and, consequently, more homogeneous films with an increased level of physicomechanical properties. 

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