Rifra uses the most advanced tools to carry out tests and trials |
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Italian technology plast / April 2025 |
depends on the temperature, in order to analyse and identify the molecules in the samples as well as to analyse mechanical properties such as elastic modulus, elongation and tensile strength. Prototypes of films and moulded parts were also produced.
STEP III Tests were conducted on cast film pilot plants with the aim of exposing the criticalities of polymers processed at certain temperatures due to the presence of contaminants which generated cracks in the film. Continuing the tests on mechanical properties, a statistical variability and dispersion of data was found that was associated with a lack of compatibility between the various components of the resin. To overcome these issues, antioxidants were added in order to counter oxidative degradation, as well as compatibilisers useful for managing different contaminants( e. g. PET + PA) and other specific additives to improve mechanical properties.
After choosing the categories of raw materials to be tested, a test matrix was defined combining
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the active ingredients to be added to the polymers under study in different percentages. The output of this matrix represents the data set at the basis of a predictive mathematical model. Operationally, compounds with a known polymer matrix and additives have been created with the aim of improving the PCRs currently available on the market. Therefore, several blends with variable concentration of compounds were created, which were then extruded with the addition of the additives mentioned above at variable concentrations. The extrusion process was repeated to simulate the oxidative stress observed on PCR resins. The compounds, once produced, were moulded to make specimens for tensile test, whereby the following properties were assessed: tensile strength, elastic modulus and area under the curve. The data are still being processed, but it is clear that the addition of antioxidants protects the resin at high temperatures and that the use of compatibilising agents up to a percentage of 5 % improves dispersion. At higher concentrations, they also contribute to the improvement of the specific value. As far as the tests performed on the cast film are |
concerned, a relevant fact is that working at medium-high process temperatures improves the looks of the product and considerably reduces the cracks that would otherwise appear on film samples.
CONCLUSIONS The study currently underway at Rifra will make it possible to identify one or more active ingredients to be proposed in the form of additives to improve the quality of PCRs. The results will be published after the termination of the project, with the aim of maximising cooperation along the plastics processing chain and thus contributing to the improvement of the quality of production processes for these resins. Regardless of the specific results, beneficial side effects have been observed such as the acquisition of new knowledge and the generation of analytical models that Rifra will make available to anyone who needs them, in the perfect spirit of the company’ s payoff“ Completiamo il tuo processo( Completing your process)”, the mantra that has sustained the company along its 46 years in business.
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