The influence of the content and composition of polymeric petroleum resins (PPRs) on the proper ties of incongealable sealants based on butyl rubber was studied. It was shown that the introduction of PPR B grade increases the adhesion ability of these sealants to duralumin. It was concluded that use of the acid-base approach is a good tool for explaining the nature of adhesive relationships.
The use of thermoplastic starch in compositions based on polylactic acid is of interest from the point of view of controlling the physicomechanical properties of materials and the time of biodegradation. The effect of thermoplastic starch containing sorbitol and / or glycerin as plasticizers on the resistance of compositions based on polylactic acid to thermal and thermomechanical action was studied. The physicomechanical properties of the compositions and their resistance to biodegradation under composting conditions have also been determined.
While producing polymers as well as during their processing, a certain amount of stabilizers is introduced into the product, which should ensure polymer properties saving during processing and those of polymer products during storage and operation. However, in cases where medical products based on polypropylene are subjected to radiation sterilization, there are not enough stabilizers in it to save their characteristics during operation. In this regard, we made an assessment of the influence of processing conditions on the properties of polypropylene with a different set of stabilizers in the manufacture of products based on it, in order to assess the degree of influence of each technological operation, including the effects of ionizing radiation during sterilization. Processing and radiation exposure are shown to affect the properties of polypropylene. Nevertheless, the effect of ionizing radiation with an absorbed dose of 40-60 kGy exceeds the negative effect of thermo-oxidative breakdown greatly during the extrusion of PP. Polypropylene containing organophosphorus stabilizers (brand PP 1562R) is more susceptible to breakdown. This is indicated by low values of oxidation induction time, breakdown initial temperature, as well as high values of MFI after exposure to electron radiation. PP brand PP H350FF/1 whose stabilizing complex contains phenol-phosphite antioxidants is more resistant to breakdown during processing and sterilization. For both brands under study, it is apparently necessary to increase the content of stabilizing additives in order to save the properties at the level of the original unexposed material.
The effect of thickness and reinforcement on the properties of the mastic layer of an incongealable sealant based on butyl rubber is studied, depending on the nature of the glued substrate. It has been established that the nature of the substrate affects the adhesive properties of the mastic. The effect of the thickness of the mastic layer on the adhesive properties is most pronounced in determining the bond strength by the tear-off method. The influence of the nature of the substrate on adhesion to the mastic layer is considered from the standpoint of acid-base interactions. The possibility and expediency of reducing the thickness of the incongealable mastic layer based on butyl rubber of the sealing coating of roofing purpose to the level of 0.5 mm without loss of quality is established. It is shown that the reinforcement of sealing coatings based on highly filled butyl rubber does not affect their vapor permeability and strength during peeling and tearing.
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