FT-IR combined with oscillatory rheology: How to evaluate chemical structure of ester derivatives of MA-containing compatibilizers.

Ester derivatives of experimental olefin-maleic anhydride copolymers synthesized at the University of Pannonia have been investigated by both classical and instrumental analytical methods that contribute to a deeper understanding of how that type of additives functions as compatibilizers for plastics and rubbers. Titration-based acid and saponification numbers have provided limited information about the chemical structure of the experimental copolymer compounds. A prompt, precise and low-cost method or combination of methods has been required to access to the ratio of the various derivatives not only straight after esterification but also for quality control during long-term storage considering the even stricter sustainability aspects either. Reproduction and scaling-up synthesises can be also followed by the combined measuring techniques of Fourier-transform infrared spectroscopy (FT-IR) and oscillatory rheometry. Structural changes occurred in the additives could be followed through monitoring their Ester Indices (EI) during the measurement, which can be connected also to the long-term properties. Experimental additives (AD) like AD-1 and AD-2 types with lower EI values of 21.5 % and 32.1 %, respectively, resulted in higher upper limits of the linear viscoelastic (LVE) range (15 % and 10 %). Conversely, the higher EI values of AD-3 and AD-4 led to significantly lower or even immeasurable upper limits of the LVE range. Additives with solid behaviour showed slight dependence on frequency above the crossover point that indicated strong connections disappearing.

Determination of the most significant rubber components influencing the hardness of natural rubber (NR) using various statistical methods.

Manufacturers use a large number of components in the production of modern rubber products. The selection of the constituents of the rubber recipe is primarily determined by the purpose of use. The different fields of applications of rubbers require the presence of appropriate mechanical properties. In this respect, it can be useful to know which substances forming the rubber recipe have significant influence on the different mechanical properties. In this study, the statistical analysis of the influence of rubber components on the hardness of natural rubber (NR) is proposed based on literature review. Based on the literature data, various statistical analyses, like linear regression, constrained linear regression, Ridge regression, Ridge sparse regression and binary classification decision trees were performed to determine which rubber components have the most significant effect on the hardness. In the statistical analyses, the effect of a total of 42 constituents of rubber compound on hardness was investigated. Most of the applied statistical methods confirmed that the traditional frequently used rubber components, such as carbon black and sulfur, have a primary effect on the hardness. However, the substances forming the rubber compound that are not widely used in practice or newly developed components appear differently in the lists of significant additives obtained by the different statistical methods.

FT-IR measurement as a simple tool for following formation of acidic functional groups in maleic anhydride containing polymers.

Titration is a measurement for maleic-anhydride containing polymers with significant chemicals consumption, time and human resource requirement meanwhile all the carbonyl groups have to be supposed to be in the cyclic form but it is not always the situation. Core of the FT-IR method has been determination of carbonyl groups in various chemical environments. The FT-IR method is developed to obtain more precise and prompt results about anhydride rings in the copolymer chain than with titration in the whole coupling number range with minimal chemicals consumption. Quantitatively apprising FT-IR results peaks of carbonyl groups have been considered since those yield well-isolated and high intensity peaks in the spectrum. Two distinct methods have been adopted for integration of areas under the selected stretching vibrations. Not all the anhydrides have been supposed to be in ring form in the copolymers but partially in acidic form that can be only taken into account by double counting during titration instead of the correctly single counting. FT-IR spectrum has been feasible for tracing that progress but titration isn't. Moreover, if difference between acid number from titration and FT-IR methods based on the chemical structure is high compatibilizing additive synthesis requires excess of reagents.•A method enabling the identification of carbonyl groups in maleic-anhydride containing polymers in various chemical environment without chemical consumption.•The method is based on the calculation of functional group ratios applying the integrated area of selected absorption peaks.

Development of Waste-Based Alkali-Activated Cement Composites.

Nowadays, global warming and the ensuing climate change are one of the biggest problems for humanity, but environmental pollution and the low ratio of waste management and recycling are not negligible issues, either. By producing alkali-activated cements (AACs), it is possible to find an alternative way to handle the above-mentioned environmental problems. First, with a view to optimizing experimental parameters, metakaolin-based AACs were prepared, and in it, waste tire rubber was used as sand replacement (5-45 wt %). Insufficient wetting between the rubber particles and the matrix was corrected through different surface treatments of the rubber. For improving the mechanical/strength properties of the specimens, fibrous waste kaolin wool (0.5-1.5 wt %) was added to the AAC matrix. Considering the results of model experiments with metakaolin, blast-furnace-slag-based AAC composites were developed. The effects of storage conditions, specimen size and cyclic loading on the compressive strength were investigated, and the resulting figures were compared with the relevant values of classic binders. The strength (44.0 MPa) of the waste-based AAC composite significantly exceeds the required value (32.5 MPa) of clinker saving slag cement. Furthermore, following cyclic compressive loading, the residual strength of the waste-based AAC composite shows a slight increase rather than a decrease.

Olefin-maleic-anhydride copolymer based additives: a novel approach for compatibilizing blends of waste polyethylene and crumb rubber.

In our work processing conditions and mechanical properties of waste polyethylene (PE)/crumb rubber (CR) blends have been improved by new types of compatibilizing additives synthesized from experimental olefin-maleic-anhydride copolymers at our laboratory. Compatibilizing additives have been introduced into the PE/CR blends in 0.2 wt% while CR concentration has been varied between 10 and 50 wt%. For comparison of the effects commercially available MA-g-PO type compatibilizing additives have also been applied. Tensile and Charpy impact tests of the compression moulded samples have been carried out. Several experimental additives have enhanced properties of the PE/CR blends either from the point of view of tensile or Charpy impact strength while commercial additives have had improving effects only on one of the abovementioned mechanical properties but not for both of them simultaneously. Since good mechanical properties could be achieved by our experimental compatibilizers good adhesion in the waste PE/CR samples have been considered and was proven by SEM graphs either.