Preparation And Properties Of The Super Absorbent Polymer And The Hydrogel Wound Dressing Composed Of PAAS/PVA

Objective:Hydrogel refers to a binary system formed by mixing water-soluble or hydrophilicpolymer with cross-linked structures and water at a certain proportion. Its core part is aslightly cross-linked macromolecular polymer with hydrophilic groups includingcarboxyl, hydroxyl, acylamino, amino and sulfonyl etc. in. It presents in its gel phase byabsorbing a large amount of liquid during hydration if dissolved in water or otherdispersed media; whereas it retains its water content, as well as its normal state, undercertain pressure. For all water-soluble or hydrophilic macromolecular compounds, theyall undergo polymerization, hydrolysis or cross-linking under certain chemical,radiating and physically biased cross-link conditions, forming three-dimensionalnetwork polymer structure which is insoluble and swelling in water. This is calledhydrogel. There are two kinds of high molecular materials that can be used to preparehydrogel. They are natural hydrophilic high molecular, including polysaccharide (fibrins,starth, chitosan, alginic acid, and hyaluronic acid etc.) and polypeptides (collagen,poly-L-glutamic acid and poly-L-lysine etc.), and synthesized hydrophilic highmolecular including polyacrylic acid, polyacrylamide, poval, polyfluoroethylene,polyvinylpyrrolidone and polymethylacrylic acid etc.. As a new functional highmolecular polymer material, the hydrogel has been applied in many fields. For example,it is used as the water sucking material of daily necessities like baby diaper and sanitarytowels, drug carrier and drug delivery materials in medical treatment and hydrogel andhydrocolloid functional dressing in wound care, for drought resisting in arid areas andseed pelleting in modern society, as water repellent and humidifying repellent ofmoisture condensation in buildings, for dehydration of crude oil and petroleum productsin petrochemical engineering, as dust suppressant in mining industry and as preservativeand thickener of food. In specific applications, different high molecular materials should be selected in different fields to meet different demands. What is of great importance isto develop a water-absorbing material with simple preparing method and goodperformance which can be applied in hygienic products; and what is of great prospectsis to develop a hydro gel with simple processing, good tensile strength and degree ofswelling to be applied to hydrogel dressing in clinical service. The paper mainly studiesthe synthesizing conditions of a new hydrogel water absorbing resin (PAAS/PVA), themeasurement of performance, and the comparison of several similar SAP materialsdomestic and abroad, and provides a new method for preparing a clean water-absorbing;then, this paper explores the preparing method and process of a new hydrogel with hightensile strength and high degree of swelling ratio, and compares it with several hydrogeldressings domestic and abroad, laying lab foundations for its use in clinical wound care.Finally, synthesized hydrogel materials are prepared after radiation processing incombination with the advantage of the high swelling ratio of hydrogel materials and thecharacteristic of good strength, with traditional rayon nettings and non-woven fabrics asthe framework, and by dressing certain amount of hydro gel stoste on the surface oftraditional materials, and a better product idea is provided to care larger wounds andwounds of larger mobility.Materials and methods:A solution with the total concentration between25%to31%is prepared with thehydrophilic high molecular materials——PAAS and PVA in different proportion. Afterbeing dissolved in high temperature, the solution is poured into the watch glass tomodule, and high-energy electron accelerator irradiation (irradiation dose:30kGy～90kGy) is used to synthesize water absorbing hydro gel material.24hours of drying isconducted at50℃through air dry oven, then Anjiesunfeng grinder is used to grind thematerial, then methanol solution with certain concentration is used to wash it, and thenstandard sieve is used to screen, and in the end the SAP product is achieved. Inaccordance with the ISO17910standard, moisture content, pH value, distilled waterabsorbent capacity, normal saline absorbent capacity, swelling rate, and centrifugalliquid preservation are determined, the influence of irradiation dose and polymerproportion on performance is analyzed, and comparison with domestic and foreignproducts is conducted. If it is freeze-thaw after irradiation, many hydro gel films areprepared under different polymer ratios by the method of combining high energy electron beam irradiation (45kGy) and thawing (four hours at-20℃and two hours at25℃, repeated twice). Measure their water content, gel proportion, distilled waterswelling (dry sample), distilled water swelling (wet sample), normal saline waterswelling (dry sample), normal saline water swelling (wet sample), tensile strength, andelongation at break respectively. The influence of polymer ratio on its performance isanalyzed and a comparison of hydro gel film materials of different characteristics andthe several hydro gel dressings in domestic and foreign markets is conducted. Dressdifferent hydro gel stoste of5ml,20ml and22ml on non-woven fabrics of36*20c㎡with traditional gauze and new non-woven fabrics as the framework (four proportions ofhydro gel stoste are25:2,25:6,18:10and20:12). Then have it irradiated by placing iton an irradiation board with a layer of plastic wrap. The specific conditions are asfollows: the energy is10Mev, the beam is8.5mA, the transmitting speed is3m/min andthe irradiation dose is45kGy. Prepare synthesized hydrogel dressing through tworecycling freeze thawing processing after irradiation. Measure the swelling degree ofdistilled water and normal saline to select the suitable hydrogel dressing type. Hydrogeltype suitable for combining with dressing is further explored to find out the suitableadditive amount of hydrogel liquid, and finally determine the most preferable preparingprocessing.Results:1．PAAS/PVA super absorbent polymer：The super absorbent polymer withsuperior properties could be obtained under the condition of raw material ratio of25:2and the irradiation dose of45kGy. Water content:1.82%±0.27%,the absorbent capacityof distilled water:502.6±14.6(g/g); the absorbing capacity of normal saline:48.8±2.3(g/g);the absorbent rate:32.0±2.4(s);the preserving water capacity aftercentrifugalism:41.8±1.6(g/g).The results indicated that PAAS/PVA SAP obtained underthe condition has high absorbent capacity、absorbent rate and preserving water capacityafter centrifugalism。2．PAAS/PVA hydrogel dressing：The hydrogel dressing with superior propertiescould be obtained under the condition of raw material ratio of20:12and the irradiationdose of45kGy followed by two freeze-thaw cycles. The tensile strength:2.752MPa.elongation at break:507.8%.degree of swelling in distilled water(wet samples):35.3× 100%, degree of swelling in distilled water(dry samples):98.9×100%. degree ofswelling in normal saline(wet samples):7.0×100%, degree of swelling in normal saline(dry samples):16.6×100%. The results indicated that PAAS/PVA hydrogel dressing hashigh tensile strength and elongation at break.3．PAAS/PVA composite hydrogel dressing：By the scaffold of a piece ofnon-wovens(36*20c㎡)，The hydrogel dressing could be obtained under the conditionof raw material ratio of25:2and the irradiation dose of45kGy followed by twofreeze-thaw cycles. According to unit mass，the absorbing capacity of normal saline:14.11±0.19(g/g). the absorbent capacity of distilled water:54.44±3.66(g/g).Conclusion:1. Water absorbing is prepared through irradiation cross-link with the liquidabsorbing capacity raising first and then lowering following the change of PVA content.The capacity raises first and then lowers as the irradiation enhances. All the otherindicators including pH value and water content etc. reach the demand of withISO17910standards on physical hygienic water absorbing materials, and especially, theliquid absorbing ability of distilled water enhances obviously and the pH valueapproaches7and some other performance has exceeded the standard of SAP domesticand abroad.2. The cross-linking of the polymer can be achieved through electron beamirradiation and freeze-thawing method. As PVA content and the total concentration ofthe system increases, the gel fraction, swelling ratio, and elongation at break are alldemonstrated by the trend of lowering first and then raising; and the tensile strengthappears as increasing gradually. Two preferred ratios of25:6and20:12are determined,and comparing the prepared hydro gel film with similar products domestic and abroad,the advantage of hydro gel film in swelling and tensile strength is far more obvious thanother similar products.3. Hydrogel and Aixing thin high strength non-woven fabrics are combined withcertain proportion, resulting in the preparation of water absorbing hydro gel synthesizednon-woven fabric dressing with the non-woven fabrics as the framework. Such materialis as light as common non-woven fabrics but the seepage absorbing capacity is highlyimproved. Compared with hydro gel film dressing, this synthesized can be prepared intolarge-scale dressing which is suitable for larger wounds and wounds of larger mobility.