Development and characterization of polymerc materials with high moisture retention performance

In all processes from production to consumption of energy; ensuring the security of supply considering our national priorities, conduct studies relating to combating climate change and reducing dependence on foreign energy and the Ministry of Natural Resources is located in the Strategic Plan 2010-2014. For this purpose by the Ministry of Energy and Natural Resources stated that the work will be carried out towards the target of reducing energy consumption and increasing efficiency. As well as energy consumption is an issue that also takes care of the customer. The low energy consumption of the product used is very important for both the individual economy. All sectors are being studied for the reduction of energy consumption by improving energy efficiency. In the white goods sector as in other sectors, these studies are quite prominent. These improvements will be made in the energy consumption of commonly used in dishwashers is why the house is very important. In the conventional drying process in the dishwasher, the water temperature in the final rinse step is up to about 65 °C and therefore energy consumption is relatively high. In this study, developing a kind of polymeric material which has high moisture retention capacity was aimed to used at drying operation of dishwasher. For this purpose, humid air passed through the chamber containing the polymeric material bu using a fan. Thus, the air will be dryed while polymeric material holding moisture then material will be regenerated by heating at washing operation in the next cycle. Thus, we aim to reduce the energy consumed by the dishwasher. The polymeric material is not present in a product market is used for this purpose. Drying in a dishwasher using zeolite in the present case can be made, although not very common. Moisture holding capacity of the zeolite is about 25 % by mass range. The biggest advantage of the zeolite according to the technology of polymeric materials developed in this study, the potential for moisture retention is much higher than that of zeolite. By weight of moisture-holding capacity of the developed material is intended to be at least 70 %. There are also significant differences in temperature between SAP's regeneration with zeolite. The regeneration temperature is dependent on the type of zeolite with the temperature of the regeneration is determined for a zeolite commercially 300-350 °C. The regeneration temperature of the superabsorbent polymer is about 50 to 90 °C. Thus, the main purpose of energy efficiency will be provided more efficiently. In this work, moisture absorption performance of acrylic based super absorbent polymers which are known with their water absorption performance has been worked. Two different methods of superabsorbent polymer synthesis was carried out. The products obtained were conditioned at two different conditions which are provided by climate chambers. The first of these conditions is 27 °C and humidity of 80 % and the second at 40 °C and humidity of 100 %. Moisture retention performance of the product is determined by measuring the weight increase and the thermal gravimetric analysis method. On the other hand water retention of polymers were also tested by resting them in pure water throughout one day at room temperature by measuring their dry weigth and swelled weight. In the first method super absorbent polymers based on the monomers with a fixed concentration of acrylamide and sodium acrylate were prepared by polymerization using ammonium persulfate as an initiator and N,N-methylenebisacrylamide as a crosslinking agent. Reaction was carried out with stirring at 80˚C under nitrogen atmosphere. In this method, super absorbent polymers were synthesised by varying the weight ratio of crosslinker. Water retention performance of products are varying from 330 to 400 wt %, moisture retention performance are varying from 16 to 22 wt %, at first conditions and from 28 to 50 wt % at the second conditions. In the second method, super absorbent polymers based on acrylamide and sodium methacrylate were prepared by simultaneous free radical polymerization in aqueous solution using ammonium persulfate as an initiator and N,N,N',N'-tetramethylethylenediamine as an activator at room temperature. Polymers were prepared with a fixed concentration of monomers by varying crosslinkers ethyleneglycol dimethacrylate or 1,4-butanediol diacrylate as crosslinkers. When ethylene glycol dimethacrylate was used the water retention performance is varying from 41 to 48 % wt, moisture retention performance was varying from 28 – 30 wt % at first conditions and the from 72 to 77 wt % at the second conditions; When 1,4-butanediol diacrylate was used the water retention performance was varying from 32 to 170 % wt, moisture retention performance was varying from 25 – 28 wt % at first conditions and the from 71 to 82 wt % at the second conditions. Moisture retention performance of super absorbent polymers which were obtained with second method is higher polymers obtained with the first method. This is the most important advantage and brings second method into the forefront. Additionally, second method does not require heating process, nitrogen atmosphere, yield shorter times than first method. It requires only stirring process. The other advantage of second method is removing the product easly from beaker in contrast to first method which is extremely important in terms of applicability. These are will be important in view of mass production for energy saving and time management. In this manner energy saving which is the main objective will be efficient. For these reasons, second method is selected. Firstly, two series of polymers were synthesised with ethyleneglycol dimethacrylate and 1,4-butanediol diacrylate by varying amount of crosslinker. After determination of their water and moisture retention capacities, 1,4-butanediol diacrylate was choosen as crosslinker because super absorbent polymers included 1,4-butanediol diacrylate have higher performance than polymers included ethyleneglycol dimethacrylate. Moreover, 1,4-butanediol diacrylate chains in the structure is longer than ethyleneglycol dimethacrylate as a result of this polymers included 1,4-butanediol diacrylate have bigger gaps in their poymer network. Thus; water molecules have much more place for adsorption. In addition this, in reaction formulation amount of 1,4-butanediol diacrylate less than ethyleneglycol dimethacrylate. For these reasons 1,4-butanediol diacrylate has various advantages. Secondly, crosslinker concetration was determined. In the series of polymers with 1,4-butanediol diacrylate were investigated in terms of moisture absorpition capacity by weight incerease method, thermal gravimetric analysis and a programaed test in climatic chamber which was simulated as a drying prosess of a dishwasher. At the and of these studies B_3 coded sample were selected as main formula. It is konown that, crosslink density of polymer increaes, water absorption capacity decreases significantly. On the other hand, crosslink denstiy is not enough polymer becomes water soluble. Because of these reasons, determining the crosslinker concentration was the most important parameter in the super absorbent polymer synthesis. After determination of formulation moisture retention performance was studied according to time. For this purpuse weight of the samples which were conditioned at second conditions previously was measured at specific time intervals and moisture retention performance is determined by using the method of weight increase. When significant differences in time dependent moisture retention were noticed, It was decided to investagate particle size and shape effects. To begin with, particle shape effect was studied and polymerization was carried out in a mold was thereby obtained in the same sized polymer particles. Performance tests have shown that the moisture retention performance over time the particles of equal size are the same. The effect of the particle size was investigated after obtaining this result. Moulds of different sizes were used to obtained polymer particles of different sizes and moisture retention effect of particle size on performance was studied. Test results showed that performance and rate of moisture retention were affected by particle size seriously and particle size decreases performance and rate increases. On the other hand there is a lower limit for particle size to avoid fuzziness problems in dishwasher system. In these circumstances particle diameter of 4 mm was set at a suitable value. In the next phase of the study, the cycle tests were conducted for the selected formulation and particle size. The aim of cycle tests was determine whether the drop in performance when when absorption - desorption cycle is repeated. Four-cycle test was realized and it was determined there is no performance degradation for products. The other stage of the study are testing regeneration. It was studied on the regeneration temperature and time for the selected B_3 formulation and determined particle size. Samples were conditioned for 24 hours in the second conditions, their moisture absorbtion capacities were determined as 250 – 260 wt %, then regeneration tests were performed for 3 hours at 70°C 80°C, 90°C and 100°C. According to these tests when regeneration temperatures were 70°C 80°C, 90°C and 100°C, moisture retention ratios were determined as 18,42, 13,60, 11,19 and 6,99 % wt, respectively. The final stage of this study was to examine ambient humidty and temperature on moisture retention, seperately. In order to this, two different sets of experiments were performed. In the first set, moisture retention performance was investageted by changing temperature at fixed humidity as 95 %. In the second test, humidity was varied when temperature was fixed as 40°C. Results of these tests show that moisture retention performance increases when temperature and humidity were increase. Additionally, it was observed that increased humidty was accelerated increasing of moisture retention performance strongly. At the end of the study, it was said that, a polymeric material could developed with desired performance. Moreover, ıt was predicted that make the pore structure of the material will increase the speed to keep moisture which is vital dishwasher application.