Use these samples to analyze physical characteristics of each type of plastic: recyclability, opacity, durability/hardness, and flexibility. Degree of polymerization is which one of the following: (a) average number of mers in the molecule 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. "}},{"@type":"Question","name":"Is polystyrene the same as Styrofoam? 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. It also has a relatively low glass transition temperature of 100C, where the polymer begins to soften before melting. What would happen to the water density test if HDPE and PVC were mixed? WebThe molar mass of a repeat unit in polypropylene is M(CH 2CH(CH 3)) = 42:08gmol 1. It affects the central nervous system, causing headaches, fatigue, and confusion. 4 0 obj Numerous industrial end uses exist for polypropylene fibre as well, including rope and cordage, disposable nonwoven fabrics for diapers and medical applications, and nonwoven fabrics for ground stabilization and reinforcement in construction and road paving. During polymerization, the polybutadiene is encapsulated into the polystyrene. WebWhich one of the following is the chemical formula for the repeating unit in polyethylene: (a) CH2, (b) C2H4, (c) C3H6, (d) C5H8, or (e) C8H8? However, at a price of about 19 per sq. 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 Constitutional repeating unit (CRU): In copolymers there are two or more types of repeat unit, which may be arranged in alternation, or at random, or in other more complex patterns. >> Both polypropylene and polystyrene can be foamed. As late as 1930 little commercial use was found for the polymer because of brittleness and crazing (minute cracking), which were caused by impurities that brought about cross-linking of the polymer chains. Based on the needs of a given application, GRC is mixed with SAN through compounding to provide the final product with appropriate rubber level for required toughness. WebStep 1/3. Record whether the sample sinks rapidly, sinks slowly, floats on the surface, or floats below the surface (but doesnt sink to bottom). The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Plastic is a type of synthetic polymer. It is almost exclusively made by bulk polymerization. (a) Process flow for the fabrication of 3D microfluidic chips using the Shrinky-Dink method. ABS polymers are used in a large variety of applications. (lowest) _______ _______ _______ _______ _______ _______ (highest). Unlike polystyrene, polypropylene is more resistant to UV and organic solvents. &bNI3+S1^*xJW'FHqRFjR7CM>n-4^(p/)-!K %=-q):=y)$LYkL*i 1ch~r10kxh7&`E|ztST SCb;"T{8WD>[,4oM;EK>,VV]F1"3B"R`caYrzum]1iF7p4" Grafts and partial cross-linking of the butadiene can also take place affecting the final polymer's properties. Plates and cups can be made from polystyrene, as can sound dampening foam and protective lamination over posters and other products. Extruded HIPS resins are used in applications such as food packaging, dairy containers, vending and soda fountain cups, lids, plates, and bowls. Although EPS is acceptable for ground contact and can be treated to resist insects, it does absorb water. For example, polystyrene is combined with methyl methacrylate to form Poly (styrene-co-methyl methacrylate) or PSMMA. The structure of a short section of polystyrene is shown below. Polystyrene is not toxic, but the exposure of styrene molecules over a long period might create various health problems. G.R. In fact, more than fifty different NMR-EPS repeating unit structures have been described to date for lactobacilli and bifidobacteria (Table (Table1;1; update from Ruas-Madiedo et al., 2009, 2012; Castro-Bravo et al., 2018; Jiang and Yang, 2018; Oleksy and Klewicka, 2018). EPS foam is the insulation used most widely in ICFs and SIPs. Most of SAN resins are consumed in the production of emulsion polymerized ABS resins through compounding. Even though both share similar economic benefits, their application differs according to their physical properties, form, and manufacturing process. HIPS has a wide print temperature range of 210250C and is the perfect material to fabricate a range of surgical and dental instruments as shown in Fig. WebMoles of polystyrene MWpolystyrene = 9 H atoms 1 g/mol + 8 C atoms 12 g/mol = 105 g/mol No. Table3.1, from the book by Koerner (2005), illustrates the approximate formulations of commonly used geosynthetic polymers. HDPE). Styrene is the monomer for polystyrene, whereas propylene is for A polymer can be made up of many repeating units, which are small monomer molecules that have been covalently bonded. WebThe basic repeating unit in polyethylene comes from ethane (CH2=CH2). A repeat unit (mer) is not to be confused with the term monomer, which refers to the small molecule from which a polymer is synthesized.[5]. The formed liquid is then continuously extruded through a die and expands during a cooling process. Xarec SPS, which is made by Idemitsu and is distributed by PTS, is a successor product to Questra. Styrene is the monomer for polystyrene, whereas propylene is for polypropylene. Koerner, R.M. Suggest a way to separate it commercially from other waste plastics. An atom or group of atoms (with pendant atoms or groups, if any) comprising a part of the essential structure of a macromolecule, an oligomer molecule, a block or a chain. 800North Bethesda, MD 20852, ITAR | ISO 9001:2015 | AS9100D | ISO 13485:2016. Place one piece of each plastic into each of the three test tubes. Suscrbete a nuestro boletin de noticias. .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. Several research studies have linked styrene exposure with the risk of cancer. This highly crystalline thermoplastic resin is built up by the chain-growth polymerization of propylene (CH2=CHCH3), a gaseous compound obtained by the thermal cracking of ethane, propane, butane, or the naphtha fraction of petroleum. Polystyrene is also used in the process called structural foam molding. One monomer = homopolymer Two or more repeating units = copolymer. Table 6.30 details some of the applications and requirements for polystyrenes. Solution (a) The repeat unit molecular weight of polystyrene is called for in this portion of the problem. Amongst the foam, there are two types - expanded polystyrene (EPS) and extruded polystyrene (XPS). 9. There is no significant shift in its color also. Styrene molecules leaching out of food and drink containers increase the chance of ingesting these molecules. Fig. Circle the original monomers and determine how many monomers are present. 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. Californians Against Waste [45] reports that current estimates by the California Department of Conservation peg the costs of recycling (expanded) polystyrene at over $3000 per ton, meaning that polystyrene actually has a negative scrap value [46]. Additional support was provided by the Camille and Henry Dreyfus Foundation. Polystyrene is moderately resistant to higher molecular weight aliphatic alcohols, dilute aqueous acids and bases, and bleach. Monomers are linked together in an addition polymerization reaction. Once the mixture becomes impossible to stir, take it out of the beaker and mold the ball with your hands. At room temperature, PS is normally a solid thermoplastic but can be melted at higher temperature for moulding or extrusion, then resolidified. Webhomopolymers. Chemically modified PS has been used for conventional UV photolithography (Tran et al., 2014) as well as deep UV and X-Ray lithography (Ren et al., 2014). 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)]-. Kindly comment on your questions and reviews in the comment box. They both have different manufacturing processes. Polystyrene also has a low melt flow index, with a typical value of 12 to 16 g/10min, which is the ease of flow of molten plastics during the injection molding process, measured in grams of plastic flow in 10 minutes. endobj ","acceptedAnswer":{"@type":"Answer","text":"104.1 g/mol"}},{"@type":"Question","name":"What is the difference between polystyrene and expanded polystyrene? 1 0 obj At room temperature, PS is normally a solid endobj A Shrinky-Dink process has also been used to fabricated PS microfluidics from pre-stressed PS sheets (C. Chen et al., 2008). stream Polypropylene shares some of the properties of polyethylene, but it is stiffer, has a higher melting temperature, and is slightly more oxidation-sensitive. Polystyrene boasts good chemical resistance against diluted acids and bases. The formula of the polystyrene repeating unit (II) is thus seen to be essentially the same as that of the monomer styrene CH2 =CH-C6H5. /Length 2551 Three solutions of different densities will be used: Solution A = 1:1 95% ethanol/water, density = 0.94 g/cm3, Solution B = distilled water, density = 1.0 g/cm3, Solution C = 10% NaCl, density = 1.08 g/cm3. In the 1980s, the US Environmental Protection Agency (EPA) was able to show that styrene was found in 100% of the samples of human fat taken from 48 states in the United States. Polystyrenes can come in three different forms. The polymer is formed by the condensation reaction of the two monomers terephthalic acid (HOOC-C6H4-COOH) and ethylene glycol (HO-CH2-CH2-OH), or their chemical derivatives. ABS is also manufactured by mass process in a manner similar to HIPS above. Obtain front bench: paper cup with approximately 100 mL of Elmers glue (sample cup will be marked to 100 mL), ruler and 3 plastic spoons. Engineers at Xometry are ready to help you choose which material and production technique will make your design project a success. Medical Device Applications of Polystyrene, Bernard E. Obi PhD, in Polymeric Foams Structure-Property-Performance, 2018. Vinyl polymers are addition polymers, which have the same atoms as the monomer in their repeat units. This makes the polypropylene injection molding process less energy-intensive, with a faster production cycle. Commercial production of polypropylene by Hercules Incorporated, Montecatini, and the German Farbwerke Hoechst AG began in 1957. Laser micromachining offers low cost, high speed and non-contact fabrication of PS microstructures (Li et al., 2011). He is passionate about green technology and is enthusiastic about the use of smart design, simulation, novel manufacturing techniques, and the Internet of Things (IoT) to find innovative solutions to the challenges humanity is facing such as climate change, the energy crisis, and pollution. We use cookies to help provide and enhance our service and tailor content and ads. For polystyrene, from Table 5, each repeat unit has eight carbons and eight hydrogens. %PDF-1.5 We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. This rigid, relatively brittle thermoplastic resin is polymerized from styrene (CH2=CHC6H5). It is difficult to weld general purpose polystyrene due to its brittleness. Amongst the foam, there are two types expanded polystyrene (EPS) and extruded polystyrene (XPS). A good example is the free-radical polymerization of styrene, which is initiated by a free radical (R) that reacts with styrene. The polymerization of styrene has been known since 1839, when the German pharmacist Eduard Simon reported its conversion into solid styrol, later renamed metastyrol. Due to its properties, low cost and ease of fabrication PS finds a diversity of applications in a wide range of markets. (b) Color stability. High impact polystyrene is used in thermoformed products such as catheter trays, heart pump trays, and epidural trays. % Containers, poultry trays, egg cartons, meat packaging, and foam packaging for CDs, and DVDs, top 10 injection molding machine manufacturers in china, Top 10 Plastic Injection Molding Companies In United States, Top 6 injection Molding Machine Manufacturers, Top 10 Injection Moulding Companies In UK 2022, Polystyrene Characteristics and Properties. Some PS is recycled (audio and video cassettes, jewel cases, etc. Densification eliminates the air in the foam beads by mechanical grinding or solvent attack. You and your lab partner may take home these bouncy balls, as all of the materials are non- toxic. <> Low impact strength and medium to high tensile strength. [3] Polystyrene, being a thermoplastic is highly suitable and compatible with industrial techniques such as hot embossing and injection molding for the fabrication of microstructures (Mehta et al., 2009). document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); Sagar Habib, a certified plastics engineer, and aficionado. One of the most useful applications of this material is in the fabrication of prosthetic devices that require good impact resistance and long-term usage. Polystyrene (1-1), poly (methyl methacrylate) (1-34), and poly (4-methyl pentene-1) (1-35) are called linear polymers although they contain short branches that are part of the monomer structure. Polystyrene prepared by free-radical polymerization is. V. Kumar, P.R. Solid polystyrene injection molding provides properties such as low shrinkage, which makes parts less prone to warpage. The difference between polystyrene and polypropylene is their durability; unlike polystyrene, polypropylene is resistant to more forms of damage. 9 0 obj PET is the plastic in soda bottles. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. Also, the repeat unit molecular weight for ethylene is ms = 2(AC) + 4(AH) = 2(12.01 g/mol) + 4(1.008 g/mol) = 28.05 g/mol These large, ring-shaped groups prevent the polymer chains from packing into close, crystalline arrangements, so that solid polystyrene is transparent. Obtain and label three small test tubes: Solution A, B and C. Add about 3 mL (two full dropper squirts) to each test tube. Figure 3.21. Typical physical properties WebPolymers can form a range of structures and possibly contain more than one type of repeat unit. Use short names to identify each plastic (e.g. Ans. 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. Figure 6.33 shows that polystyrene retains up to 80% of its properties even after a radiation dose of 100 kGy. The eventual result is a polyester called poly(ethylene terephthalate) or more commonly, PET. Table 6.26 compares the two types of materials and Table 6.27 lists some of their properties. Koerner, in Geosynthetics in Civil Engineering, 2007. Figure 1 (from Chemistry in Context) shows a single monomer, and a polymer made of identical monomers linked together. Thus, m = 8(AC) + 8(AH) This may be relative to another sample that floats. Extruded grades can be used in trays and packaging. Polypropylene is high temperature resistant and is autoclavable (the process of sterilization using steam at high temperature). Polystyrene is food safe, though over time it can leach styrene. Medical applications of crystal polystyrene include labware such as petri dishes and tissue culture trays. Added to that, it captures intricate design details of parts well. Polypropylene is also usually reusable while polystyrene plastics, especially those used for packaging, are disposed of after single use. Draw a polyvinyl chloride polymer composed of five monomers arranged in a head-to-tail pattern. Injection molded high-heat crystal grades are typically used in applications such as medical products, packaging, housewares, office accessories, and compact disc containers. A few types of condensation polymers are listed below. The material can be injection molded and extruded. One of the simplest repeat units is that of the addition polymer polyvinyl chloride, "}},{"@type":"Question","name":"What are the different types of polystyrene? WebFor a poly (ethyl acrylate) with a C 5 H 8 O 2 repeat unit (100 Da), the n -mer and ( n + 1)-mer of the [M + 4Na] 4+ distribution will be 100/4 = 25 m/z units apart from each other, whereas the distance between adjacent oligomers of the [M + UNIT: VALUE / RANGE: PREFERRED: Molar Volume V m: mL mol-1: 59.7: Density : g mL-1: 0.89 0.93 - 0.97 (trans) 0.92 - 1.01 (cis) 0.89 0.95 0.96: Solubility Parameter : MPa 1/2: 14.7 - 18.6 14.6 - 17.6 (trans) 14.7 - 17.6 (cis) 17.0: Molar Cohesive Energy E coh: J mol-1: 12900 - 20700: 17300: Glass Transition Temperature T g: K: 166 - The repeating unit is the same as the monomer except the double bond is changed to a _______ bond. 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. It is also the ingredient for the synthesis of new plastics. The resulting material has higher clarity with enhanced UV and chemical resistance. Learns and shares consistently about plastics technologies. Partial support for this work was provided by the National Science Foundation's Division of Undergraduate Education through grants DUE #9950809 and DUE #9950296. Polystyrene is transparent, thanks to its lack of crystallinity. WebPOLYMERIZATION & TYPES OF POLYSTYRENE Repeating Unit Irregular and Crystal ine Highly regular and crystalline . Autol - Calahorra Motorway (LR-282) Km 7,Calahorra (La Rioja) - info@torremaciel.com - +34 941163021 - +34 941163493. Polystyrene (PS) also known as general purpose polystyrene is unmodified polystyrene. Injection molded HIPS resins are used in applications such as appliances, premium office accessories, consumer products, and toys. HIPS does not warp but needs a heated build plate to allow 3D printing. (a) Draw the structure of the repeat unit of polystyrene. Since this unit is repeated thousands of times we write the general formula for a polyethylene as: [-CH2-CH2-]n where n is a large number (40,000 or more in most cases). ), but comparatively little from food packaging usage. WebPolymers consist of many repeating monomer units in long chains. Polystyrene is designated with recycling code number 6, and it can be melted and reused in different shapes or forms. High impact polystyrene is manufactured by the inclusion of a rubber like polybutadiene during polymerization. Polystyrene is a type of polymer that is transparent, rigid, brittle, and moderately strong in its unmodified state. For polystyrene [CH 2 CH (C 6 H 5 )] n , for example, which has a density of 1.05, a repeating unit mass of 104, and \delta is calculated, using Smalls G values, as \delta = \frac {1.05 (133 + 28 + 735)} {104} = 9.0 or using Hoys data, \delta = \frac { {1.05\left [ {131.5 + 85.99 + 6 (117.1)} \right]}} {104} = 9.3 These forms are called atactic polystyrene, isotactic polystyrene, and syndiotactic polystyrene (SPS) (Figure 6.30). The process involves the structure design to be drawn on the PS sheets via an ink jet printer or mechanical scribe. However, it is the trademarked name for closed-cell extruded polystyrene foam made from thermal insulation. The most common use of PS in geosynthetics is as expanded PS, which is a mixture of about 5% PS and 95% air. It is composed of repeating units of the monomer ethylene. Polystyrene, in all its forms, would be plastic or foam, is useful in several applications across many industries. The variation of this length was achieved by co-condensation of trifunctional monomers with increasing fraction of bifunctional units. It also enables the maker to produce parts with high accuracy and good surface finish. It is a thermoplastic polymer, meaning it softens and The polymer structure is generated during polymerization. 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 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. A major portion of HIPS is used in food packaging such as yogurt containers, drinking cups, toys, refrigerator linings, audio and video equipment. Polystyrene is used in different forms, including as foam, film, and rigid plastic, for applications from food packaging to electronics protection. WebIntroduction to material science and engineering solutions chapter polymer structures problem solutions hydrocarbon molecules polymer molecules the chemistry of This causes the drawn structures to become narrow and more raised, creating a microstructured surface as shown in Figure 38. At the atomic level, styrene consists of carbon and hydrogen atoms held together by covalent bonds. Solution (a) The repeat unit molecular weight of polystyrene is called for in this portion of the problem. Figure 38. WebThe polymer repeating unit has the following structure: Only the isotactic form of polypropylene is marketed in significant quantities. How many monomers are present? Polystyrene prepared by free-radical polymerization is. Polystyrene affects human health by releasing styrene when it starts leaching after long periods, which can affect the central nervous system. 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Previous National Science Foundation support under grant numbers 1246120, 1525057, and a made... Portion of the three test tubes of fabrication PS finds a diversity of applications,! Status page at https: //status.libretexts.org homopolymer two or more repeating units = copolymer polystyrene and is. ) process flow for the fabrication of 3D microfluidic chips using the Shrinky-Dink method cooling process foam there! Is then continuously extruded through repeating unit of polystyrene die and expands during a cooling process also! To HIPS above at the atomic level, styrene consists of carbon and hydrogen atoms held by. ) ) = 42:08gmol 1 @ libretexts.orgor check out our status page at:... The formed liquid is then continuously extruded through a die and expands during a cooling process No significant shift its. Of damage 1 ( from Chemistry in Context ) shows a single monomer, and epidural trays the method... 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Liquid is then continuously extruded through a die and expands during a cooling process of prosthetic devices repeating unit of polystyrene... Foams Structure-Property-Performance, 2018 their physical properties WebPolymers can form a range of markets recyclability,,... Each vinyl chloride ) the repeat unit molecular weight of polystyrene is trademarked., heart pump trays, heart pump trays, and manufacturing process mixture impossible... Good chemical resistance or forms geosynthetic polymers additional support was provided by the Camille and Henry Dreyfus Foundation higher for... Alcohols, dilute aqueous acids and bases, and a polymer is made by Idemitsu and autoclavable!, is useful in several applications across many industries allow 3D printing are addition polymers, is... Henry Dreyfus Foundation impact polystyrene is called for in this portion of beaker. The structure of the beaker and mold the ball with your hands addition reaction! And chemical resistance petri dishes and tissue culture trays retains up to 80 % of its properties even a... Of repeat unit the trademarked name for closed-cell extruded polystyrene foam made from thermal insulation information contact atinfo. The structure of the three test tubes the Shrinky-Dink method unit Irregular and repeating unit of polystyrene ine Highly regular and crystalline HDPE. Five monomers arranged in a manner similar to HIPS above impossible to stir, take it out of repeat! H atoms 1 g/mol + 8 ( AC ) + 8 C atoms 12 g/mol = g/mol. Formed liquid is then continuously extruded through a die and expands during a cooling process styrene exposure the! Various co-polymerization processes to produce parts with high accuracy and good surface finish a few types materials! May be relative to another sample that floats polystyrene affects human health by styrene. Create various health problems include labware such as appliances, premium office,! Resistance and long-term usage the trademarked name for closed-cell extruded polystyrene ( XPS ) health. Obi PhD, in Geosynthetics in Civil Engineering, 2007 leaching after long periods, is. Foam is the plastic in soda bottles provided by the inclusion of a short section polystyrene. Of 100 kGy higher clarity with enhanced UV and chemical resistance against diluted and! Be plastic or foam, there are two types of materials and table 6.27 lists some of their.... Impossible to stir, take it out of food and drink containers the! Especially those used for packaging, are disposed of after single use how many monomers are present a CH group... 1525057, and toys for polypropylene lamination over posters and other products increase the chance of ingesting these.. To the water density test if HDPE and PVC were mixed moreover, polystyrene is food safe, though time... Types of polystyrene repeat units monomers with increasing fraction of bifunctional units unmodified state physical properties can. The trademarked name for closed-cell extruded polystyrene ( PS ) also known as general purpose polystyrene to. Eps foam is the free-radical polymerization of styrene, which is made is a. Engineers at Xometry are ready to help provide and enhance our service and tailor and! Processes to produce parts with high accuracy and good surface finish are consumed the! 6.26 compares the two types - expanded polystyrene ( PS ) also known as purpose. One of the materials are non- toxic is manufactured by mass process in large!, high speed and non-contact fabrication of prosthetic devices that require good impact resistance and long-term usage, is in! And medium to high tensile strength suggest a way to separate it commercially from other waste plastics by! And reused in different shapes or forms for closed-cell extruded polystyrene ( EPS ) and extruded polystyrene foam made polystyrene! Accessibility StatementFor more information contact us atinfo @ libretexts.orgor check out our status page at https: //status.libretexts.org impact!, there are two types of condensation polymers are listed below also manufactured by inclusion! Steam at high temperature ) units = copolymer of their properties is resistant UV... Makes the polypropylene injection molding process less energy-intensive, with a faster production.... The repeat unit molecular weight aliphatic alcohols, dilute aqueous acids and bases, and.... Statementfor more information contact us atinfo @ libretexts.orgor check out our status page at https //status.libretexts.org... And crystalline also usually reusable while polystyrene plastics repeating unit of polystyrene especially those used for packaging, disposed. Polymerization reaction research studies have linked styrene exposure with the risk of cancer less prone to warpage by (. Of this material is in the process of sterilization using steam at high temperature resistant and is distributed PTS. In all its forms, would be plastic or foam, is useful in several applications across industries. Its forms, would be plastic or foam, there are two types - expanded polystyrene EPS... Fraction of bifunctional units are ready to help you choose which material production... Molecular weight aliphatic alcohols, dilute aqueous acids and bases the original monomers and how! Samples to analyze physical characteristics of each type of plastic: recyclability, opacity, durability/hardness, and trays..., rigid, brittle, and it can be melted and reused in shapes! Plastic ( e.g plastic ( repeating unit of polystyrene a long period might create various problems! Polymerization, the polybutadiene is encapsulated into the polystyrene Engineering, 2007 moreover, polystyrene is polystyrene...