polyvinyl alcohol purchase

Polyvinyl alcohol (PVA) is a widely used synthetic material. PVA ability to dissolve in water and break down naturally makes it a good choice for packaging films. The main production methods for PVA film are aqueous solution coating and melt blow molding. PVA is hard to shape with heat because it melts at a higher temperature than it decomposes. This is due to the strong links between its molecules and its crystal structure. Therefore, the most important factor in the processing of PVA film is the selection of appropriate additives.   1. Effect of Plasticizer Amount on Tensile Strength, Tear Strength, and Elongation at Break of Polyvinyl Alcohol Film As shown in Figure 1, film ability to resist breaking lessens as more plasticizer is added. This suggests that plasticizers reduce how strong the film is. The plasticizer gel theory explains that when the plasticizer mixes with the resin, it loosens the points where the resin molecules connect. These connections have different strengths. The plasticizer pulls them apart and hides the forces that hold the polymer together. This reduces the secondary forces between the polymer macromolecules, increases the flexibility of the macromolecular chains, and accelerates the relaxation process. Tensile strength goes down as you add more plasticizer. As the amount of plasticizer is increased, the film becomes more flexible and stretches further before breaking. This suggests that plasticizers make the film more pliable. Plasticizers achieve this by weakening the attraction between the large molecules in the polymer. This increased flexibility and longer relaxation period lead to the film ability to stretch further. The data indicates that as more plasticizer is added, the film becomes easier to tear. This likely happens as the plasticizer reduces the film's surface energy and lessens the energy needed for both plastic flow and lasting deformation. These factors, in turn, contribute to the film's reduced resistance to tearing.   2. Effect of Crosslinker Amount on the Tensile Strength, Elongation at Break, and Tear Strength of PVA Film As shown in Figure 3, the film's tensile strength goes up gradually as the amount of crosslinker is increased, during which the elongation at break goes down gradually. When a certain point is reached, the film's tensile strength goes down gradually, while the elongation at break goes up gradually. At first, as more crosslinker is added, the number of working polymer chains goes up, intermolecular forces get stronger, and the polymer chains become less flexible. The ability of the large molecular chains to change shape and rearrange decreases while the chain relaxation is difficult. So, the tensile strength goes up, while the elongation at break goes down. Continuing the use of crosslinkers causes degradation and branching to increase gradually, which decreases the number of working polymer chains, and increases the flexibility of the polymer chains. The ability of the large molecular chains to change shape and rearrange increases, while the chain relaxation becomes easier. As a result, the tensile strength starts to go down again, while the elongation at break goes back up. As shown in Figure 4, the tear strength of the film changes with the amount of crosslinker. At first, it goes up, but then it starts to go down. This happens because when crosslinking starts, more crosslinker helps the polymer network form. This makes the film's surface energy go up gradually. It then needs more energy to spread plastic flow and irreversible viscoelastic processes. Because of this, the film's tear strength gets better as crosslinking happens. But, if there is too much crosslinker with too much polymer broken down, and there are more branching reactions, the tear strength gets worse.   3. Conclusions When you add more plasticizer, PVA film becomes less strong but stretches and tears more easily. When you add more crosslinker, film strength and resistance to tearing improve at first, but then weaken, while its ability to stretch keeps getting better.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com

Gloves are the most commonly used protective tools in the laboratory besides goggles. There are many types of gloves, and different gloves have different uses.     1. Natural rubber (latex) Latex gloves, made from natural rubber, typically lack a lining and are available in both clean and sterile versions. These gloves can provide effective protection against alkalis, alcohols, and a variety of chemical dilution aqueous solutions, and can better prevent corrosion from aldehydes and ketones.   2. Polyvinyl chloride (PVC) gloves The gloves do not contain allergens, are powder-free, have low dust generation, low ion content, strong chemical corrosion resistance, can protect almost all chemical hazardous substances, and also have anti-static properties. Thickened and treated surfaces (such as fleece surfaces) can also prevent general mechanical wear, and thickened types can also prevent cold, with an operating temperature of -4℃ to 66℃. Can be used in a dust-free environment. PVC gloves grading standards: Grade A products, no holes on the surface of the gloves (PVC gloves with powder), uniform powder, no obvious powder, transparent milky white color, no obvious ink spots, no impurities, and the size and physical properties of each part meet customer requirements. Grade B products, slight stains, 3 small black spots (1mm≤diameter≤2mm), or a large number of small black spots (diameter≤1mm) (diameter>5), deformation, impurities (diameter≤1mm), slightly yellow color, serious nail marks, cracks, and the size and physical properties of each part do not meet the requirements.   3. PE gloves PE gloves are disposable gloves made of polyethylene. These gloves are waterproof, oil-proof, anti-bacterial, and resistant to acids and bases. Note: PE gloves are safe to use with food and are non-toxic. It is better to keep PVC gloves away from food, especially if it's hot.     4. Nitrile rubber gloves Nitrile rubber gloves are usually divided into disposable gloves, medium-duty unlined gloves and light-duty lined gloves. These gloves can prevent erosion by grease (including animal fat), xylene, polyethylene and aliphatic solvents; they can also prevent most pesticide formulations and are often used in the use of biological components and other chemicals. Nitrile rubber gloves do not contain protein, amino compounds and other harmful substances, and rarely cause allergies. They are silicone-free and have certain antistatic properties, which are suitable for the production needs of the electronics industry. They have low surface chemical residues, low ion content and small particle content, and are suitable for strict clean room environments.   5. Neoprene gloves Similar to the comfort of natural rubber, neoprene gloves are resistant to light, aging, flexing, acid and alkali, ozone, combustion, heat and oil.   6. Butyl rubber gloves Butyl rubber is only used as a material for medium-sized unlined gloves and can be used for operations in glove boxes, anaerobic boxes, incubators, and operating boxes; it has super durability against fluoric acid, aqua regia, nitric acid, strong acids, strong alkalis, toluene, alcohol, etc., and is a special rubber synthetic resistant liquid gloves.   7. Polyvinyl alcohol (PVA) gloves Polyvinyl alcohol (PVA) can be used as a material for medium-sized lined gloves, so this type of gloves can provide a high level of protection and corrosion resistance against a variety of organic chemicals, such as aliphatic, aromatic hydrocarbons, chlorinated solvents, fluorocarbons and most ketones (except acetone), esters and ethers.   Website: www.elephchem.com Whatsapp: (+)86 13851435272 E-mail: admin@elephchem.com