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1The effect of ethyl alcohol on the mechanical parameters of optical fibers in an acrylate protective coating
M. Naparin1'2*, N. Kasatkin1,2, J. Lapteva1
1- Public Joint Stock Company "Perm Scientific-Industrial Instrument Engineering Company", Perm
2- Perm State University, Perm
In the absence of data concerning the adverse effects of ethyl alcohol on acrylate protective coating (PC), ethyl alcohol is employed during the processing of optical fibers (OF). It is used for cleaning the ends of OF from dirt and stripped PC, for degreasing purposes during cable laying or for installation of optical systems. The research project in question considers the impact of ethyl alcohol on the mechanical parameters of fibers.
The samples were placed in the desiccator (Fig. 1) and incubated for periods from one hour to five days in ethyl alcohol and its vapours. Following each soaking period, the following parameters were measured: the degree of polymerisation of the secondary PC and the ultimate strength, which was determined by the two-point bending method. The results of the optical microscope inspection revealed that direct contact of ethyl alcohol with acrylate PC leads to the formation of defects and complete peeling of PC after interaction for 12 hours (Fig. 2).
Fig. 1. Desiccator.
Fig. 2. Microscope examination results.
Fig. 3. Results of ultimate strength and degree of polymerization.
The onset of the interaction between ethyl alcohol and acrylate coating is assumed to be due to the presence of microcracks on the coating surface during the operation or manufacturing of the OF, into which the ethyl alcohol enters.
In order to demonstrate the nature of the changes of parameters as a function of exposure time, an object with a slow reaction - OF in ethyl alcohol vapour - was considered. The graph (Fig. 3) shows the change in the degree of polymerisation and the ultimate strength from the time of exposure of the sample in alcohol vapour. From the results obtained, the ultimate strength and the degree of polymerisation are related. A decrease of polymerisation and ultimate strength indicates an increase in the local defect concentration on the PC. Presumably, polymer restructuring (breaking/crosslinking of polymer chains) takes place in the 6-12 and 96 hours exposure, which may be accompanied by the formation of new microcracks on the surface. In the case of that, there is a high probability of the formation of "voids in the coating", leading to coating peeling (Fig. 2). After 12 hours of exposure to ethyl alcohol, a large number of areas of completely delaminated PC are formed (Fig. 4).
Fig. 4. A fragment of an entangled section of the winding.
Reduction in mechanical parameters and peeling of the coating can potentially lead to malfunction of optical systems with this OF (drops of alcohol may remain on the OF sections when buffer coating is applied). Ethyl alcohol can act as an aggressive medium for the acrylic PC during prolonged interaction. During the study, hypothesis is proposed that exposure of OF with acrylate PC to ethyl alcohol or its vapours could be used as a technique to assess the quality of the acrylate PC promptly.
