cross linked polyacrylate copolymer experiments

In the absence of water, the polymer chain is tightly twisted and coiled, so the connection points are tightly buried inside the nugget. When absorption stops, the polymer crystals have expanded to about300 timestheir original weight. This phase of crack growth is thermally activated, strongly time dependent, and generally consumes most of the time to fracture of the specimen. Instant Snow can be found at many online retailers and stores all year round for just a few bucks. Study Osmosis: Place several cups out with 1 tablespoon of sodium polyacrylate in each one. Kids will be excited to witness the magic of Insta-Snow as you explain to them how this substance changes from a liquid to a solid. Eventually, this oily concoction can cause a reduction in the number of places on the polymer that can hook to water, which means a loss of absorption. In the case of rather weak filler materials (such as dolomite) toughening will be limited by transverse particle fracture. Good diapers use a polymer that turns into a gel. At a certain critical crack length aII, Gc becomes larger than the material resistance and the excess released energy is used to drive the crack even faster: the crack therefore accelerates (Cantwell et al. Theydry out as plants use the water they hold and then re-hydrate when water is present in the soil again. Theyrenot supposedto be eaten and can be a choking hazard if used carelessly. Like other nanomaterials, nanogels have nanoscale physical properties, such as size (20200nm) and large surface area [55,57]. Swelling equilibria is thus important. Sun. String Slime that contains a thermochromic color-changing dye. Alternatively, there has also been increasing interest in using nanosized hydrophilic, High Performance Polymer Nanocomposites for Structural Applications, Polymer Matrix Composites with Roughly Equiaxed Reinforcements: Microstructure and Mechanical Behavior, Encyclopedia of Materials: Science and Technology, is the molecular weight between cross-links, is the fraction of elastically effective chains in amorphous regions. Washing your hands before handling the crystals not only prevents dirt from getting into your experiment, but it also helps prolong the life of the crystals and keeps them looking fresh. Rainbow Test Tube: Introduce colored crystals into the mix and for a science lab with a creative, artistic twist. Bhardwaj, in Materials Under Extreme Conditions, 2017. fabricated drug-loaded core-shell hybrid nanogels that have the function of tumor imaging, local hyperthermia, temperature sensing, and triggered drug release [68]. Cold Crystals: Place a zipper-lock bag of the hydratedpolymer in the freezer. Columbia, SC 29201, CLICK HERE to report State Agency Fraud (Office of the Inspector General). Therefore, NIR light and magnetic field are able to induce localized heating and trigger the release of drugs. Highly efficient loading capacity of a wide range of drugs due to the prolonged residence time provided by mucoadhesive polymers [50]. Therefore, gauze coverings are used along with them to hold them appropriately on the wound. Snow cant be brought inside for study or playing with friends. This conclusion is always true regardless of the type of primary chain distributions since no primary distribution is assumed in the equation derivation. No matter what quantity of Insta-Snow you choose, youll get all of the materials you need in this comprehensive kit, including mixing instructions and an in-depth scientific explanation about polymers. Targeting ligands can include various compounds, such as antibodies, peptides, hormones, receptor ligands, nucleic acids, lipid derivatives, etc. A large number of cross-links would make the material rigid, hard, and closer in properties to a thermoset (Fig. This sounds like anothergreat science fair project. They are considered as ideal dressings as they clean, rehydrate dry and necrotic tissues and initiate autolytic debridement. The best part? The more water thats available, the more the polymer will unwind to get it. When it comes into contact with water it absorbs all of it very quickly and is really light and fluffy just like snow! If you pour each color of snow in layers into a large vase and wait a week, youll see them start to blend and create color mixtures. Add salt to your already made snow. Successive branching with H-type cross-linkages leads to gel formation. Just add water to make gallons of white fluffy snow in seconds! Instead, toss them into the trash, but remember why they were made: polymers are designedto be environmentally beneficial. Vinny R. Sastri, in Plastics in Medical Devices (Third Edition), 2022. Compare the length of chilling time and the temperatures reached forfrozen crystals toa similar amount of ice made from regular water. Oh, the wonder of polymers! It is assumed that every monomeric unit in the primary chains has an equal probability to be cross-linked. Plus, its just good practice to always wash your hands before and after doing a science experiment. For many systems KIc and E are seen to increase linearly with f up to moderate filling fractions (Spanoudakis and Young 1984, Moloney et al. By continuing you agree to the use of cookies. s, and 0.0037PV of high concentration slug was injected followed by post-gel water drive. Water-absorbing crystals introduce students to polymer science. Educators have found great uses for instant snow from early childhood sensory tables to advanced chemistry experiments. In the last decade, there has been increasing interest in the applications of nanogels as drug carriers and imaging agents [50,55,56]. In addition it can be concluded from fractographic and microscopic analyses (Smith 1989, Cantwell et al. We use cookies to help provide and enhance our service and tailor content and ads. Figure 6. S. Zhu, A. Hamielec, in Polymer Science: A Comprehensive Reference, 2012. So, when snow (and fun) is on the mind, let your your young scientists experience hours of entertainment with the Steve Spangler Science Insta-Snow Powder kits, delivering realistic and fluffy snow that can be dried out and reused countless times. Such products have applications as ion-exchange resins, chromatographic packings, superabsorbent materials, contact lenses, photoresists, and drug deliveries. Meanwhile, nontoxic hydrophilic outer shells provide outstanding blood biocompatibility, such as, polyvinyl alcohol (PVA), PEG, and monomethoxy poly-(ethylene glycol) (mPEG), which has also been widely applied in surface modification of other kinds of nanoparticles, such as liposomes and gold nanoparticles [48]. 5(a)). 12 - 5 p.m. The network structure of cross-linked polymers is characterized by the higher density of cross-linking points (as compared to the density of entanglement points in thermoplastics) and the consequent reduced deformability of the chain segments. Primary chains are rather imaginary and would exist if all cross-linkages were severed. Glass fiber, carbon fiber, and natural fibers are the traditional choices and several commercial applications have been developed using them. Since they have nearly the same index of refraction as that of the water around them, since theyre 98% water, light passes straight through them and the surrounding water so you cant see them. We like to add the water quickly so it self-mixes and really explodes! 1987, Kinloch and Young 1983, Cantwell and Roulin-Moloney 1989)is subject to stress concentration and local plastic deformation leading to crack tip blunting. Georgios M. Kontogeorgis, in Computer Aided Chemical Engineering, 2004. JULIUS CAESAR: ROMAN MILITARY MIGHT AND MACHINES, Museum Open This Weekend Buy One, Get One General Admission, Museum Operating Status Closed Due to Inclement Weather, PAST EXHIBIT Hall of Heroes Blockbuster Exhibition, PAST EXHIBIT: The International Exhibition of Sherlock Holmes, RACE: Are We So Different? Schematic presentation of cross-linking (gelation) in free-radical copolymerization of vinyl/divinyl comonomers.43, Given a population of primary chains [Pr] having a total of Q1 monomer units, the development of polymer molecular weight with cross-linking prior to gel formation can be followed by, where kx is the cross-linking rate constant. How dothe dry nuggetscompare to each other in size? described a novel self-assembled nanogel consisting of hyaluronic acid-epigallocatechin gallate conjugates (HAEGCG), cytotoxic protein Granzyme B (GzmB) and linear polyethylenimine (PEI) [63]. (4). Distilled water is like rain water and lacks the minerals, chemicals and other dissolved materials that can change how the polymer bondswith it are removed by distilling, so you get the best, most reliable results by choosing distilled water. Polymeric nanoparticles are nanosized colloidal particles and have been extensively explored for drug delivery for cancer therapies. Let hydrated clear or colored crystals completelydry outon a cookie sheet. Each student can even grow and take home their own crystal rainbow test tube. The tip of this crack constitutes a process zone, whichas in a pure resin (Moloney et al. What happens? Compared with polymer injection, when gel was injected, the wellhead injection pressure increased by 4.14MPa, the permeability significantly decreased, the residual permeability reduction factor increased from 1.326 to 1.403, and water intake thickness increased to 19%. Thats right, superabsorbent polymers are used to lock moisture in baby diapers so that they dont leak. A polymer is a very long chainthats made up of identical molecules. This instant snow product is recommended for children ages four and up with adult supervision. One small 3.5oz jar mixed with gallon of water will yield 2 gallons of snow! For the same quartz flour-filled epoxy resin discussed in Sect. 10 a.m. - 5 p.m. Monday Friday Distilled water is usually easy to obtain and is not very expensive. The presence of well-bonded particles influences the toughness, KIc, positively (by crack pinning and bowing, void formation, and crack bridging). Insta-Snow isnt just a cool demonstration tool. Our Instant Snow Powder kit is a true wonder and a versatile learning aid for the classroom or playtime. 1987, Nakamura and Yamaguchi 1993). What changes do you notice? It is also assumed that there are no chain cyclization reactions involved. Place 1 teaspoon of nuggets into a quart-sized plastic bag. Its recommended thatdistilled water be used to soak the nuggetswhen possible. See text for details (after Smith 1989). 3.9). A variety of fillers are used to improve modulus of thermosetting polymers. It has been observed that this nanogel efficiently kills CD44-overexpressing cancer cells and shows little toxic effect to normal cells [63]. As indicated in Sect. Widely used divinyl monomers are divinylbenzene and ethylene glycol dimethacrylate. The resulting fracture surface of such a debonded zone is rather smooth. The reader is referred to [48,51,52] for an in-depth investigation and discussion of recent advanced PHAs, CDs, and PLGA-based polymeric nanoparticles used for cancer treatment. Theres no stirring required. Posted by SC State Museum on Jan 8, 2016 in Education, Educational Resources | Comments Off on LAST MINUTE LESSONS: Super Cool Science with Sodium Polyacrylate, Here at the South Carolina State Museum, one of our favorite winter activities uses a very simple powder called sodium polyacrylate. Prior to cross-linking they can be monomers/oligomer (liquid) or molten polymer filled in a mold of predefined shape and size, where insitu cross-linking takes place. Thats a great question and a great idea for a science fair project. Why should you wash your hands before handling the water jelly crystals? Copyright 2022 Elsevier B.V. or its licensors or contributors. 10 a.m. - 5 p.m. Zhonglei He, James F. Curtin, in Applications of Targeted Nano Drugs and Delivery Systems, 2019. 6). Try to break a nugget into smaller pieces with dryfingers. Hui Wang etal. Hence, they are blended with natural polymers to form composites that balance the advantages of each material. Compare bygrowing the same kind of seeds in plain soil and compare the growth in two-day intervals for one or two weeks. Theyll support plant growth for about six years. If you wore a modern diaper at one point in your infant life, then youve actually already had experience with one type of these chemicalmarvels. Think about your answers on a molecular level and try to explain the changes that you have observed. Plus, weve been told by people doing this experiment that the crystals can grow larger when absorbing distilled water. The defect grows (often rather slowly) forming a subcritical crack. Our Insta-Snow provides plenty of discussion opportunities as everyone observes its physical change and response to temperature. Each link gets larger as it hooks up to more and more water. : Bguelin, in Encyclopedia of Materials: Science and Technology, 2001. Discover the presence of UV energy, and how special dyes in the beads produce colors. Known as a superabsorbent polymer, this chemical is commonly found in diapers (which is why we often do diaper science with it, too). Such dressings also possess low mechanical strength and are quite difficult to handle. Wash your hands and then scoop a handful of the cool, shimmery lumps out of the bag. It melts! Salt breaks down the polymer links and releases the water quickly. Keep track of your discoveries and youre on your way to a science fair project. At intermediate temperatures a limited number of debonding events occur before the onset of crack propagation (in this case there is limited volume damage). Polymers are very common you see and use them every day: theyre found in silk, wool, nylon, cotton, cellulose, proteins, rubber, PVC, epoxy materials, silicone, hair conditioner, paint, polystyrene, adhesives, gelatin, Silly Putty, polyester, Kevlar, CDs, eyeglasses and Teflon, just to name a few. 1988) that at low temperatures, high stresses, and short times to fracture a single debonding event can initiate rapid brittle fracture (Fig. The average polymer concentration was 630mg/L and the average crosslink concentration was 27.6mg/L with the ratio 22.8:1. 1988). In a constant load experiment, the stress intensity factor, Kc, and energy release rate, Gc, will grow with crack length, a. The energy release rate, GIc, of a filled resin generally is also larger than that of the pure resin; however, the relationship between GIc and f depends on filler size and interfacial adhesion. Observe the crystals after 10 minutes, 30 minutes and 1 hour. Dont dispose of the crystals, either wet or dry, down the drain, as they will certainlyclog the pipe. 3.1, in a strained filled thermoset essentially two local deformation mechanisms are observed: particlematrix debonding and microshear banding. Using suitable initiator, a sensitizer or radiation, monomers/oligomer (liquid)/molten polymer transform into a highly rigid three-dimensional structure. The long, randomly coiled, loosely cross-linked materials can be stretched easily but return to their original shapes when the force or stress is removed. What is it thatfills the hydrated jelly crystals? This particular polymer puffs up a little too big to successfully be used in diapers. Meanwhile, the hydrogel shell can control the release of drug and fluorescence intensity by varying environmental temperature, which is based on the thermoresponsive poly-(N-isopropylacrylamide-co-acrylamide) [68]. Basic fracture mechanisms can be well observed in creep at constant load. What other differences, aside from size, do you notice? Fracture starts from a pre-existing defect (frequently at the surface and not always visible). During this phase of growth the crack extends from one debond to the other more or less within a plane. Place the bag into abowl to catchany slow leaks. Hydrogels are synthetic cross-linked polymers that are usually made from polymethyl methacrylates and polyvinyl pyrrolidine and are capable of absorbing and retaining a significant amount of water when placed at the wound site [127]. With wp(r)=2rexp(r), eqn [257] can be easily solved (hint: (1wg)rexp(wgr) with very small ), resulting in the widely used CharlesbyPinner equation:188. where ws is the sol fraction, ws=1wg. Sat:: Use a ruler to measure their size and compare one of the hydrated crystals to a drynugget. Various copolymer technologies continue to bring new elastomers to the market. HA is known to have the ability of targeting CD44, which is overexpressed in many cancer cell types, and EGCG is used to facilitate the formation of stable nanogels. If you look very carefully, you can just see the edges of each crystal where light is bent slightly as it passes through the polymer. It should be pointed out that the above treatment and derivation of eqns [248][258] are based on a statistical argument that polymer networks are randomly assembled from primary chains at any cross-link density. The chain begins to swell on the outside, which allows more water to get into the polymer to available link points, further expanding. The Water Jelly Crystals can be used not only for a lot of fun activities, but also for practical purposes. The crack then jumps from one debond to another, more or less within a plane and a smooth subcritical crack zone is formed (Fig. You can add color later! The release of the drugs and other molecules is easy to control by varying the nanogel properties, for example, by incorporating stimulus-responsive cross-linkers or changing cross-linking density [50]. Unlike real snow, this wont melt everywhere or turn into puddles. In the Water Jelly Crystals experiment, youll start with little nuggets that look like rock salt and end up with huge, gleaming, water-filled blobs. However, the swelling of cross-linked polymers can be estimated with such equations. If a second radical adds to the pendant double bond, a H-type cross-linkage is formed and the chain is branched. 301 Gervais Street Modeling of the reinforcing effect of well-bonded particulate charges on subcritical crack propagation in filled thermosets through (a) crack pinning (Lange 1970, Evans 1972) and (b) crack deviation (Spanoudakis and Young 1984). The crystal is now about 98% water and 2% polymer. Just add water and watch in amazement. This bonding and swelling continues until there are no more available places to collectwater. How well doseeds germinate and grow in a cup of hydrated polymer without soil? When a polymer radical propagates with a double bond on a divinyl monomer, the unreacted double bond on the same monomer molecule becomes pendant on the chain. Cosmically Cool Summer Fun at the State Museum Get Tickets Today! 1988) that debonding occurs ahead of the crack tip. Freeze it itll feel just like real snow and you can make snowmen out of it! You can use candy to discover the ways molecules interact and behave. These properties of nanogels make them promising for applications in antiskin disease, antiinflammatory, ocular, transdermal, and protein/peptide drug delivery and therapy, cancer drug delivery, and imaging [50]. Schematic representation of crack propagation mechanisms in a highly filled epoxy resin. The cross-link density can be calculated from, Solving eqns [249][252] gives the number- and weight-average chain lengths as. ScienceDirect is a registered trademark of Elsevier B.V. ScienceDirect is a registered trademark of Elsevier B.V. Electrochemical Power Sources: Fundamentals, Systems, and Applications, Polymers for Advanced Functional Materials, Polymer Science: A Comprehensive Reference, Condensed Encyclopedia of Polymer Engineering Terms, Polymer FloodingFundamentals and Field Cases, Computer Aided Property Estimation for Process and Product Design, The role of biopolymers and biodegradable polymeric dressings in managing chronic wounds, Advanced Textiles for Wound Care (Second Edition), Ring-Opening Polymerization and Special Polymerization Processes, Plastics in Medical Devices (Third Edition), Combination Strategies for Targeted Delivery of Nanoparticles for Cancer Therapy, Applications of Targeted Nano Drugs and Delivery Systems, . Mon: Have several cups of water (6oz) ready and dyed different colors with food coloring. As everyone knows, snow is a seasonal phenomenon. Explore the fun side of learning using the ever-changing science of polymers. Fill a clear container with plain water and dump four or five of your largest crystals intoit. What changes to the polymer do you see? These multifunctional nanoparticles have high photoluminescence, photostability, magnetic/NIR-heat conversion ability, and drug-accumulation potential due to the composite structure consisting of fluorescent carbon dots, a porous carbon shell, and superparamagnetic iron oxide nanocrystals. He has related the increase in toughness to the ratio of particle size, r, to spacing, c. Silica and alumina composites correspond quite well to the approximation thus obtained for rectangular particles (Moloney et al. Let the soaking continue overnight, then observe the crystals again to see what changes have occurred. Highly branched or cross-linked polymer materials can be obtained through copolymerization of vinyl/divinyl monomers. Thats a lot of science! Cross-linking and crystallinity are often visualized as similar (in some sense) phenomena and are described with the same theories: crystalline regions are assumed to act as physical or giant cross-links. They shrink back to their original size and can be stored and re-hydrated many times. 1988). PurilonTM (Coloplast) and Nu-gel TM (Johnson and Johnson) are widely recognised hydrogels for wound healing purposes [127129]. At the gel point, the weight-average chain length approaches a theoretical infinity and gel molecules start to form. 5(c)). There is a lot of science to be discovered in a bag of candy that goes way beyond tasting it and enjoying it. Pebble sized superabsorbent crystals that can absorb up to 300x their weight in water. To account for the crystalline/cross-linking effect, an additional factor (elastic term) is typically required in thermodynamic models. Since the crystal is mostly water, it washes your hands as you handle it. Learn about sunscreen and SPF. Two popular theories to account for this effect are the Flory-Rechner52: As observed from these equations, both theories introduce at least one extra parameter, which needs to be determined from experimental data: the molecular weight between crosslinks Mc and the fraction of elastically effective chains f. They have been combined with free-volume models7,54,55 and they have been applied to semicrystalline polymer/solvent systems. Turn a bottle of soda & a roll of Mentos into an erupting geyser that will launch up to 30 feet! Each batch of snow will become a different color! Well-bonded, rigid particles act as an obstacle and force the crack to bow (or to deviate) as it passes between neighboring filler particles (Fig. Maybe you could you use frozencrystals the next time you need an ice pack. In reality, gel molecules are gradually built up during polymerization, which is dependent on history. Thats a lot of water. The perfect slime for Halloween, but is sure to amaze and excite any time of year. When you order any of the all-in-one science kits from Steve Spangler, youre get a true wow factor and tons of real-life, scientific applications. Check outVanishing Jelly Marblesfor more ideas. This fake snow wont feel fake at all. Explore the science of building polymers. Color Fizzer Tablets are best or food coloring can work. This acceleration marks the transition from the second to the third phase of crack growth. Think of these linksas tinysponges waiting to connect with water molecules. Testit you might be surprised. Remove three or four Water Jelly Crystals from the bag and put them on a plate. ), Our Vulnerable Democracy: Past, Present, and Future (Virtual Series), Visit the State Museum and Escape From Earth, Apollo 16 & Beyond: South Carolina in Space NEW, Show and Tell: Recent Acquisitions at the State Museum, Show and Tell: Adquisiciones recientes del Museo Estatal, Haz un poco de ruido: La ciencia del sonido, Apollo 16 & Beyond: South Carolina in Space. In compressive loading (of the same quartz flour-filled epoxy resin) matrix shear, particlematrix debonding, particle fracture, and matrix microcracking by linking up of debonded zones are observed in this order. Kausch, Ph. Disappearing Crystals: Turn your experiment into a magic trick: the hydrated crystals can vanish if you know the secret. The Learning Opportunities of Playing With Snow Its good advice to keep the crystals away from your mouth, ears, eyes and nose, as usual. 5. This buildup can lead to dirty and smelly crystals that are no fun for anyone. Stir the crystals using your hand foran interesting sensation. NOTE: If youre planning to havecolored crystals, its easier to start with the color ofwater you wantbefore youtoss in the nuggets. Polyhydroxyalkanoates (PHAs) [51], cyclodextrins (CDs) [52], and poly-(lactide-co-glycolic acid) (PLGA) [53] are the most commonly used polymer materials for the core fabrication [48]. How did they become so soft in water? If this is your first time working with Water Jelly Crystals, dont usecolors so you can see what to expect. However, Water Jelly Crystals are not consideredto be a health hazard. Depending on the volume damage ahead of the crack, on the toughness of the matrix, and on temperature, there are three modes of crack extension, which are illustrated in Fig. However, unlike thermoplastic nanocomposites, thermoset nanocomposites cannot be recycled and are less chemically resistant. Fill the bag withwaterand seal it tightly. When you check the bag after a few hours, those tiny nuggets havegrabbed onto water molecules and haveexploded into huge, globby, Water Jelly Crystals as a result. Recently there has been a considerable interest in using nanofillers as reinforcing agents for thermosets. The results are satisfactory but they are not predictive: the Mc and f parameters should be estimated from experimental data. At the end of gel injection (July 17, 2001), total of 0.2868PV of gel was injected which contained 473.83 tons of dry polymer and 20.54 tons of cross-link. Advisory Committee, RACE: Are We So Different? Learn about thermochromic materials and dyes. 5(a) to Fig. Your discoveries using a superabsorbent polymer have just begun. Alternatively, there has also been increasing interest in using nanosized hydrophilic cross-linked polymer networks, also termed as nanogels, for drug delivery [49,50]. 5(c) (Smith 1989, Smith et al. Now, break a Water Jelly Crystal into smaller pieces with your fingers. Figure 5. Nanogels are hydrophilic nanosized cross-linked polymer networks, also called hydrogel nanoparticles [49,50,54]. The latter three mechanisms are irreversible, and create the volume damage that is first observed close to the yield point. In this case extensive volume damage is done before the crack propagates and its extension by void coalescence involves further ductile matrix deformation (microshear banding). Evans (1972) has extended the line tension concept used in dislocation theory as suggested by Lange (1970). Jicheng Yu etal. The kit comes with the essential materials youll need to conduct 6 experiments and challenges for 1 4 children per kit. But, these dressings cannot absorb sufficient wound exudates and therefore support bacterial proliferation and lead to foul smell in the infected wound. The longer you soakthe nuggets, the more water theyll absorb. The list of polymer-containing just goes on and on, kind of like long chains of polymers. 2.2, it has been concluded (Smith 1989, Smith et al. 5(b)). The gel fraction, that is, the ratio of the number of monomeric units in gels to that of total monomeric units, can be predicted by Florys recursive equation:16, where wg is the gel fraction and wp(r) is the chain length distribution of primary chains.