{"@context":"https://schema.org","@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What is the repeat unit molecular weight for polystyrene? (1 mark) (b) Draw the structure of the monomer which Chemistry. a lightweight bottle cap? HIPS is similar to ABS as uses Limonene as a solvent during manufacture. While polystyrenes uses are flexible and it features a low shrink rate, it also flows slowly and can come out brittle. Table 6.30. Web1st step All steps Final answer Step 1/3 (a) To calculate the concentration of initiator required to prepare polystyrene with a number average molar mass of 750 kg/mol, we can use the following equation: M n = f M i 1 f Explanation: In many condensation polymers, the repeat unit contains two structural units related to the comonomers which have been polymerized. For example, in polyethylene terephthalate (PET or "polyester"), the repeat unit is -CO-C 6 H 4 -CO-O-CH 2 -CH 2 -O-. Polystyrene is also food safe, so its used in food service applications as rigid silverware and containers for food and drinks, as well as polystyrene film as part of meat and takeout packaging. Polystyrene beads were dried in a vacuum oven at 70C to remove any moisture and then weighed in a beaker on a lab-grade analytical balance having precision of 0.02mg. Benzene was added to the beaker (5mL/g benzene, of total weight of PS and carbon nanoparticles). also known as copolymers. When a thin section of molded polypropylene is flexed repeatedly, a molecular structure is formed that is capable of withstanding much additional flexing without failing. When applied as sheathing, EPS should be used over house wrap. In fact, more than fifty different NMR-EPS repeating unit structures have been described to date for lactobacilli and bifidobacteria glass or polystyrene surfaces than the parenteral strain. Discover the reasons why Styrofoam (polystyrene) is not recycled as much as it could be. Appliances use polystyrene foam as insulation, while its rigid form is used for housings and casings. Other Styrene Polymers: Several other important classes of styrene polymers are also used. Free radical polymerization of polystyrene. The low glass transition temperature is responsible for the low maximum temperature limit for prolonged use (Tg = 373 K (100C)), The material is recyclable but very expensive. For the bouncy balls you made, what is the name of the monomer? WebThe basic repeating unit in polyethylene comes from ethane (CH2=CH2). Polyvinylchloride (PVC) is composed of the vinyl chloride monomer. It is also the ingredient for the synthesis of new plastics. WebPolystyrene is a polymer made up of repeating units of the monomer styrene, which has a molecular formula of C8H8. Polystyrene is a popular material in many applications, from parts of consumer goods to insulation and packaging solutions. The process includes melting together the plastic resin and other ingredients. Another popular plastic called Acrylonitrile Butadiene Styrene (ABS) results from the co-polymerization of acrylonitrile and butadiene with polystyrene. These large, ring-shaped groups prevent the polymer chains from packing into close, crystalline arrangements, so that solid polystyrene is transparent. Effect of gamma radiation on polystyrene. A Shrinky-Dink process has also been used to fabricated PS microfluidics from pre-stressed PS sheets (C. Chen et al., 2008). fMX3LD8 ^ JmvgB,%Mog_>g*aJ2\%F)bIOCqC)ZpnW/4c^PjgKq/SNZ|g%JpIlg?L-}P"MDfd9u_g4nyu*h-% 7j>esI2&p!fZfgIWcg`[t7+]Q`[/l5J#5dbUT6]rsh;?/G[0aV-/(M S8AS70PLhM Xometry makes no representation or warranty of any kind, be it expressed or implied, as to the accuracy, completeness, or validity of the information. Building walls & roofings, refrigerators, freezers, cold storage facilities, etc. Sometimes plastic containers are made from two polymers and not just one. Polystyrene (PS) also known as general purpose polystyrene is unmodified polystyrene. Most EPS is unfaced, which means it is fragile to work with and is considered semipermeable, so it does not create a vapor barrier [54]. Examples of addition polymers: polypropylene, polyacrylonitrile, polystyrene (Monomers and polymers can have any functional group) For the exam, be able to recognize the polymer when the monomers are Figure 6.32. High impact polystyrene (HIPS) resins have characteristics such as ease of processing, good dimensional stability, impact strength, and rigidity. They both have different manufacturing processes. Suggest a way to separate it commercially from other waste plastics. Engineers at Xometry are ready to help you choose which material and production technique will make your design project a success. Polystyrene is manufactured through an extrusion process. The Jumi Application is Unpublished or Removed, International Alcoholic Beverages Expo, Guizhou, CHINA. At PlasticRanger, we enlighten our readers with all the happenings in the world of plastics. Degree of polymerization is which one of the following: (a) average number of mers in the molecule Those include copolymers of styrene and maleic anhydride for high heat applications, transparent impact polystyrene (TIPS), manufactured by anionic block copolymerization of styrene and butadiene, and expandable polystyrene, usually used as molded foam for packaging of electronic equipment, such as TV's, audio equipment and computers. Table 6.28. Push each piece under the liquid surface with a glass stirring rod. Polystyrene is not autoclavable, but other methods of sterilization such as gamma radiation are employed. It is also used as insulation in building structures. DO NOT STIR. (a) To calculate the concentration of initiator required to prepare polystyrene with a number average molar mass of 750 kg/mol, we can use the following equation: M n = f M i 1 f. Explanation: where M n is the number average molar mass of the polymer, f is the initiator efficiency, and M i is the molar mass of the initiator. Allow the ingredients to interact for 10-15 seconds. The figure below depicts polymerization of polystyrene (PS). For example, in polyethylene terephthalate (PET or "polyester"), the repeat unit is -CO-C6H4-CO-O-CH2-CH2-O-. In the early 1900s, chemists began to replicate natural polymers, and create synthetic polymers, beginning with nylon which mimics silk in its strength and flexibility. Extruded HIPS resins are used in applications such as food packaging, dairy containers, vending and soda fountain cups, lids, plates, and bowls. Learn About Polystyrene Uses, Advantages, and More. Chronic exposure to styrene is dangerous to human health. Styrene is the monomer for polystyrene, whereas propylene is for This symbol makes recycling easier by making the identification of plastics easier. What are the disadvantages of Polystyrene? Polystyrene is usually combined or co-polymerized with other compounds to form plastics with improved properties. High impact polystyrene can be welded using techniques like ultrasonic and radio frequency welding. Expanded PS used to contain chloroflurocarbons but other, more environmentally safe, blowing agents are now used. Figure 3.21. << endobj The symbol used on plastic packaging materials is three arrows in a triangle shape, with the number of plastic in the middle. Thinking about ordering polystyrene products? Polystyrene affects human health by releasing styrene when it starts leaching after long periods, which can affect the central nervous system. High impact polystyrene is used in medical parts and components and applications (like bottles and containers) where impact resistance is more important. In recent years, some high performance grades of HIPS resins have come to compete with more costly engineering resins in applications such as appliances and consumer electronics. PS for architectural and engineering applications can also be extruded into forms of standard cross-sections or into sheets with various patterns. Low impact strength and medium to high tensile strength. The recycled plastic is used in low-cost applications such as horticultural trays, wastebaskets, wood substitutes, packaging foam, and desk trays. Is polystyrene really capable of high-end engineering applications? 4. Record physical observations about the ball in the table: is the ball stretchy? Polystyrene has a chain where the substituent R is a phenyl group (C6H5), corresponding to a benzene ring minus one hydrogen: -[CH2-CH(C6H5)]n-, so the repeat unit is -[CH2-CH(C6H5)]-. Web14.4 (a) Compute the repeat unit molecular weight of polystyrene. It is produced at low temperatures and pressures using Ziegler-Natta catalysts. Syndiotactic polystyrene (SPS) is a semicrystalline polymer synthesized from styrene monomer using a single-site catalyst such as metallocene. Polystyrene is easily manufactured by the free radical polymerization of styrene using free-radical initiators (Figure 6.31). 3.21. Ans. Figure 38. Most adhesives can be used with both polystyrene and high impact polystyrene. - 0- 1 | Chegg.com. At the atomic level, styrene consists of carbon and hydrogen atoms held together by covalent bonds. Polypropylene and polystyrene are both similar in many applications, but there are some Fig. SAN is used in application where it's additional attributes such as better chemical resistance, toughness, and heat distortion temperature are most beneficial. Polystyrene is another thermoplastic film with excellent transparency, with a high tensile strength but giving a poor barrier to moisture vapor and gases (Benning 1983; Kader et al. 9 0 obj =wwN5x5nzsW>5z4J-03l{S4H=Br doT*o1]45S*&rtcbF=7bIhhGLg%P`}H$? ;gzP?5{W}tJCj$*U:J8ce\YvB5KDtc!)V. ","acceptedAnswer":{"@type":"Answer","text":"The three different types of polystyrene include polystyrene foam, polystyrene plastic, and polystyrene film. .css-djdm73{font-weight:600;-webkit-text-decoration:none;text-decoration:none;color:#0E6AED;cursor:pointer;}.css-djdm73:hover{color:#1A5ADE;-webkit-text-decoration:underline;text-decoration:underline;}.css-djdm73:active{color:#1A5ADE;}Start your quote with Xometry today. Draw the repeat unit of the polyester chain formed by reaction of ethane-1,2-diol (shown in question 3) and butanedioic acid (shown below). A major portion of HIPS is used in food packaging such as yogurt containers, drinking cups, toys, refrigerator linings, audio and video equipment. In table 1 gives the global PS and HIPS use for the main markets. ABS polymers are used in a large variety of applications. Improvement in toughness is achieved by in-situ grafting of polybutadiene rubber with polystyrene leading to increase adhesion between the rubber particles and polystyrene matrix. General purpose or crystal polystyrene is a brittle material. Polystyrenes advantages far outweigh the limitations and thus make it a go-to plastic and foam material for manufacturers. In poly (vinyl chloride) the repeating unit comes directly from the end-to-end linking of many vinyl chloride molecules. A molecule from which a polymer is made is called a monomer. Each vinyl chloride monomer molecule contributes a CH 2 group joined to a CHCl unit by a single bond. Use these samples to analyze physical characteristics of each type of plastic: recyclability, opacity, durability/hardness, and flexibility. What is the composition of polystyrene? Polyesters are condensation polymers, which contain fewer atoms within the polymer repeat unit than the reactants because of the formation of byproducts, such as H2O or NH3, during the polymerization reaction. The unreacted monomer and diluent are flashed off under vacuum leaving the high molecular weight polystyrene. S. Nauman, V. Koncar, in Smart Textiles and their Applications, 2016. The advantages of polystyrene plastic injection molding are low shrinkage, moldability, and the flexibility to be used in blended and foam form. This fatigue resistance has led to the design of polypropylene boxes and other containers with self-hinged covers. For polystyrene, from Table 5, each repeat unit has eight carbons and eight hydrogens. A polystyrene chain of N = 10,000 monomers has 2N C-C bonds. Why is it important to dislodge any adhering bubbles in the density tests? (a) Draw the structure of the repeat unit of polystyrene. However, because of its very low moisture absorption, limited dyeability, and low softening point (an important factor when ironing clothing), polypropylene is not an important apparel fibre. | The Definitive Guide. This page titled Polymer Chemistry: Polymerization Reactions is shared under a not declared license and was authored, remixed, and/or curated by David Whisnant. G.R. When the polymer is formed, the C=C double bond in the monomer is replaced by a C-C single bond in the polymer repeat unit, which links by two new bonds to adjoining repeat units. The disadvantages of the polystyrene plastic injection molding process are low melt flow index, high melting point, and a short temperature range. Its also used as polymer matrix for several composite materials. If the sample floats, it has a density lower than that of the solution. Both polystyrene and polypropylene are polymers, i.e., large molecules with repeating smaller structural units or monomers. Effect of EtO sterilization on polystyrene. The repeat unit of the polystyrene polymer is the styrene monomer, which comprises a vinyl group and a benzene ring. Samples of different plastics are available at the front bench. The electron clouds are able to absorb the radiation eliminating the generation of reactive free radicals. Ans. At room temperature, PS is normally a solid We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Table3.1, from the book by Koerner (2005), illustrates the approximate formulations of commonly used geosynthetic polymers. The two structural units in the polymer are then considered to be -CO-C6H4-CO- and -O-CH2-CH2-O-. Usually, polystyrene shrinks less than 0.5%, which is low compared to other injection molded plastics. A few types of condensation polymers are listed below.