NATURAL POLYMERS MU SCI 4_1 2018 1 NATURAL POLYMERS 4 POLYTERPENES Dr. Ladislav Pospíšil 29716@mail.muni.cz January 2018/4_1 Time schedule January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 2 LECTURE SUBJECT 1 Introduction to the subject – Structure & Terminology of nature polymers, literature 2 Derivatives of acids – natural resins, drying oils, shellac 3 Waxes 4 Plant (vegetable) gums, Polyterpene – natural rubber (extracting, processing and modification), Taraxacum_kok-saghyz 5 Polyphenol – lignin, humic acids 6 Polysaccharides I – starch 7 Polysaccharides II – celullosis 8 Protein fibres I 9 Protein fibres II 10 Casein, whey, protein of eggs 11 Identification of natural polymers Laboratory methods of natural polymers’ evaluation Isoprene – The basic molecular formula of terpenes January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 3 Vzorec Systematic IUPAC name 2-methyl-buta-1,3-dien The other name 2-methyl-1,3-butadien Summary Formula C5H8 Terpenes – the main component of RESINS Nomenclature Number of Carbon atoms Physical State at Standard temperature (i.e. 23 °C) Monoterpenoid 10 Liquid SESQUITERPENOID 15 Liquid Diterpenoid 20 Solid State TRITERPENOID 30 Solid State A bit of TERMINOLOGY is NECESSARY •POLYTERPENE = POLYISOPRENE • •Rubber > Vulcanization > Vulcanized Rubber • • •Plant (vegetable) GUMS = POLYSACCHARIDES = Mucilage (GUM) • January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 4 January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 5 polyizoprén 001.jpg polyizoprén 002.jpg polyizoprén 003.jpg Composition of the NATURAL RUBBER – it is polymer made of ISOPRENE hydrocarbon (2-methyl-buta-1,3-dien) Structure formula of the POLYISOPRENE Cis-POLYISOPRENE NATURAL RUBBER trans-POLYISOPRENE Gutta-percha Three step enzymatic synthesis of the TERPENOIDes January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 6 img555.jpg img556.jpg CONDENSATION „HEAD – TAIL“of two UNITS of so called „ACTIVE ISOPRENE“ TERPENOIDES 1 2 3 •POLYTERPENE - are contained in approx. 2000 plants from various geographic regions •Trees, Bush, Herbs •The most important is the Tree: Hevea brasiliensis •HOPEFUL HERB: Taraxanum koksagyz • • January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 7 POLYTERPENE = POLYISOPRENE Appearance in NATURE January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 8 img400.jpg img404.jpg Perhaps historical Pictures! January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 9 POLYTERPENE = POLYISOPRENE Extracting in Nature > „Field latex" • LATEX (approx. 25 – 35 % w/w of Rubber) • Coagulation by acids (formic, acetic) > CREPE RUBBER •Drying & Preservation over a Fire> Ribbed Smoke Sheet •Calendring and Stabilisation against oxidation and Microorganisms • Expedition January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 10 Přírodní kaučuk - sběr ze stromů003.jpg Přírodní kaučuk - sběr ze stromů002.jpg January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 11 str 684.jpg str 685.jpg The Layers in the Cross Section s of the Hevea brasiliensis tree stem: 1.The old dead Bark 2.The young Bark – the Rubber Latex source 3.The Cambium 4.WOOD The Composition of the Rubber Latex Particle: 1.Proteins and Resins 2.GEL of the Latex 3.SOL of the Latex LATEX (approx. 25 – 35 % w/w of Rubber) •Rubber (approx. 25 – 35 % w/w) •Water (60 – 75 % w/w) •Proteins ( 2 % w/w) •Saccharides •Inorganic Matter •Resins January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 12 img401.jpg The Cross Section s of the Hevea brasiliensis tree stem: 1.The old dead Bark 2.The yongh Bark – the Rubber Latex source 3.The Cambium 4.WOOD January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 13 Composition of the NATURAL RUBBER Values’ Range MEAN VALUES Smoked Sheets Crepes Water (% w/w) 0,3 - 1,2 0,61 0,42 Acetone extract (% w/w) 2,5 – 3,2 2,9 2,7 Proteins (% w/w) 2,5 – 3,5 2,8 2,8 Ash content (% w/w) 0,15 – 0,90 0,38 0,30 RUBBER (% w/w) 92 – 94 93,8 93,6 Chlorides (% w/w) 0,002 – 0,010 0,006 0,003 Sulfates (% w/w) 0,02 – 0,05 0,03 0,04 Sterols (% w/w) --- 0,5 0,5 Higher fatty acids (% w/w) --- 1,4 1,1 Cuprum (ppm) 2 – 10 5 4 Manganese (ppm) 0,8 – 4,0 1,5 1 January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 14 Sterols, also known as steroid alcohols, are a subgroup of the steroids and an important class of organic molecules. They occur naturally in plants, animals, and fungi, and can be also produced by some bacteria (however likely with different functions). [1] The most familiar type of animal sterol is cholesterol, which is vital to cell membrane structure, and functions as a precursor to fat-soluble vitamins and steroid hormones. 300px-Sterol_svg.png January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 15 COMPOSITION of the NATURAL RUBBER Component Content ( % w/w) Rubber hydrocarbon 35 Water 60 Resins & Fatta acids 2 Proteins 1,8 Inorganic substances & the other components 1,2 Dependance of the Density and Viscosity on the Content of the Rubber hydrocarbon Rubber hydrocarbon ( % w/w) Density (kg/m3) Viscosity (m.Pa.s) 20 996 2,5 30 983 4,0 40 972 5,5 50 959 7,5 60 948 27 January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 16 POLYTERPENE = POLYISOPRENE IZOMERs img557.jpg NATURAL RUBBER Gutta-percha •It does NOT vulcanize! • BETTER resistance to oxidation (weathering) •NOT Elastic at normal temperature • Soft and elastic at temperature over approx. 50 °C • TERMOPLAST • It is gained from another plant then NATURAL RUBBER •Vulcanization • LOWER resistance to oxidation (weathering) •Elastic at normal temperature cis trans polyizoprén 003.jpg January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 17 300px-Guttapercha_svg WIKI ENG 03012017.png Guttapercha_structure WIKI CZ 03012017.png Gutta-percha - various presentations of the MAIN CHAIN in the Literature trans-1,4 polyisoprene designation is related to the MAIN CHAIN January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 18 Gutta-percha versus NATURAL RUBBER Various presentations of the MAIN CHAIN in the Literature img650.jpg img648.jpg R is here the CONTINUATION of the MAIN CHAIN January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 19 Gutta-percha versus BALATA GUM • BALATA is very similar to Gutta-percha, but only as to the Physical Properties, not as to the chemical Point of view • BALATA is more soft > it was used for Chewing Gums, but a synthetic food analogue is used now • Its importance and use are marginal and decreasing now Manilkara bidentata is a species of Manilkara native to a large area of northern South America, Central America and the Caribbean. Common names include bulletwood, balata, ausubo, massaranduba, and (ambiguously) "cow-tree". Balata is a large tree, growing to 30–45 m (98–148 ft) tall. Its latex is used industrially for products such as chicle CHICLE is a natural gum > POLYSACCCHARIDE, not POLYTERPENE! January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 20 POLYTERPENE = POLYISOPRENE How was the Structure discovered ozonolýza přír. kaučuku.jpg It is demonstrated at Gutta-percha here, but it is the Trans Structure! •„Mastication “ –cleavage of the chains to shorter parts using mechanical energy and oxygen •Addition of the other components and kneading (homogenisation of the mixture: –Fillers (mostly Carbon black, amorphous SiO2, ……) –Plasticizers, –Pigments, –Antioxidants a antiozonants –Vulcanization agents (sulphur, accelerators, …) –Lubricants January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 21 Processing of the NATURAL RUBBER Before Vulcanisation January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 22 Processing of the NATURAL RUBBER One typical Mixture composition Component PARTS (not % w/w) Function NATURAL RUBBER 40 Synthetic RUBBER 1 30 Modification of Properties Synthetic RUBBER 2 30 Modification of Properties ZnO 3 – 4 Vulcanization accelerator Stearic acid 2 Lubricant Carbon black stiffening 30 Modification of Properties Plasticizers 4 Sulphur 2 – 3 Vulcanization Antioxidants and antiozonants 1,5 Protection against oxygen and ozone People working with Rubber and PVC ussualy do not calculate % w/w, but using PARTS! What interesting did I personally January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 23 DOCUMENTS FOR THE Court-appointed Expert •Black spot on the fairing of the Racer (motorcycle) • Is it Spot the ASPHALT or Tyre rubber? • SEM + EDX analysis of Elements in the Spot • „What was my Target“ • SULPHUR Vulcanization • ZINC Vulcanization accelerator •RESULT: NO ZINC, NO SULPHUR, it MUST BE ASPHALT Two Roll Mill (Rubber, PVC, etc.) January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 24 img561.jpg Diagram of the TWO ROLL MILL and Scheme of the Mixing and/or Mastication using it: 1.Main Frame 2.Side part of Frame 3.Shackle 4.Front adjustable Roll 5.Rare Roll with Drive 6.Bearing body 7.Doctor blade (scrubbing of the material covering the Roll) 8.Vessel 9.Emergency stop handle January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 25 img562.jpg BUNBARY Mixer (kneading machine) (The Inventor of this Machine was Mr. BUNBARY) Kneading machine: 1.Mixing Blades 2.Mixing Chamber 3.Discharge stopper 4.Stopper 5.Hopper January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 26 NATURAL RUBBER is for longest time used HYDROCARBON POLYMER! The first use of rubber was by the indigenous cultures of Mesoamerica. The earliest archeological evidence of the use of natural latex from the Hevea tree comes from the Olmec culture, in which rubber was first used for making balls for the Mesoamerican ballgame. Rubber was later used by the Maya and Aztec cultures - in addition to making balls Aztecs used rubber for other purposes such as making containers and to make textiles waterproof by impregnating them with the latex sap. Charles Goodyear developed vulcanization in 1839, although Mesoamericans used stabilized rubber for balls and other objects as early as 1600 BC Various Descriptions of VULKANISATION See the following three slides January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 27 January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 28 VULKANISATION NATURAL RUBBER By elementary Sulphur 1 659px-Vulcanization_of_POLYIsoprene_V_2.png • Mixtures with NATURAL RUBBER VULKANISE at Temperatures approx. 150 – 180 °C. • Synthetic Rubbers VULKANISE at Temperatures approx. 180 –220 °C. VULKANISATION USSUALY DOES NOT GO BY REACTION OF THE DOUBLE BONDS, THEY ARE USSUALY MAINTAINED > SENSITIVITY TO OZONE January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 29 img774.jpg Accelerator Vicinal crosslinks = CROSSLINKING at neighbouring Carbons THE ONLY THIS CROSSLINKING FORMS THE ELASTIC BEHAVIOUR VULKANISATION NATURAL RUBBER By elementary Sulphur 2 It is possible to VULKANISE by Sulphur Compounds also (here SX)! January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 30 VULKANISATION NATURAL RUBBER By elementary Sulphur 3 img651.jpg It is considered also the Bond C-C, on which one Double bond „was employed“, but it is NOT USSUAL! SULPHUR as the Atom is written as a Simplification only! You can meet so many various Schemes of the VULKANIZATION . , The Schemes 2 and 3 are PROBABLY the most realistic. January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 31 VULKANISATION NATURAL RUBBER By elementary Sulphur 4 str 796.jpg Sulphur is not one Atom, but CHAIN OF ATOMS, usually eight Sulphur Cyclooctasulfur-above-3D-balls.png The Structure of the Rubber and Vulcanise Rubber: 1.Rubber before Vulcanisation 2.Soft Vulcanised Rubber 3.Hard Vulcanised Rubber January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 32 CRYSTALLISATION OF NATURAL RUBBER str 799.jpg str 800.jpg a)Unoriented amorphous Structure b) ORIENTED semi-crystalline Structure Deformation Curves 1.Polyamide 2.NATURAL RUBBER 3. sPt – stress, e - relative deformation •The Macromolecules having the Long Chains, e.g. NATURAL RUBBER, have good possibility to be extended by hundreds percent. •The Development of the Crystallisation is clearly shown at the Stress – Strain Curves. •The Molecules are self-aligning after initial Deformation and in this Stage of the Deformation Curve is the only low Load sufficient to do high Deformation. •This Deformation and also Crystallinity is lost after Breakage of the Sample or Releasing the Mechanical Stress. Degradation of Rubber by Ozone January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 33 img775.jpg img776.jpg Ozone is the Natural part the atmosphere and is formed e.g. at Lighting (electric discharge in the atmosphere) It formed also by artificial procedure electric discharge January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 34 VULKANISATION NATURAL RUBBER By Sulphur Compounds Charles GOODYEAR (1839) – the INVENTOR SULPHUR CONTENT IS: • 1 – 5 % w/w (soft Vulcanized RUBBER ) • Up to 15 – 30 % w/w (HARD Vulcanized RUBBER, e.g. Ebonite) January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 35 Product Content of RUBBER (% w/w) Transparent Vulcanized Rubber, Dipped rubber, Rubber thread Over 80 Mixtures for Tires and Tubes (both Tread and Casing) – Car,Bike, Motocycle…. Foamed Rubber, Cables electro 50 – 80 Rubber shoes, Conveyor belts, Mechanical Rubber Goods (e..g. Holes, Waveguide, Rubber bush 30 – 50 Accumulator (Battery) casing, Flooring, Sealing (Gasket) < 30 The other % w/w up to 100 % w/w are Additives! January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 36 Sulphur Content more than 30 % w/w and more EBONITE It is also commonly used in physics classrooms to demonstrate static electricity because it is at or near the negative end of the triboelectric series. Hard rubber was used in the cases of automobile batteries for years, thus establishing black as their traditional colour even long after stronger modern plastics like polypropylene were substituted. •The Effort to develop various types of the Synthetic Rubber takes more than 100 already and are successful. •Butadiene-styrene Rubber is probably the most widespread synthetic Rubber type •NATURAL RUBBER is the Irreplaceable up to now •POLYMERISATION of isoprene is not giving the cis-isomer only > it can NOT replace the NATURAL RUBBER •The Mixtures NATURAL & SYNTHETIC RUBBER enable the Optimisation of the desired Properties • • January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 37 NATURAL RUBBER versus SYNTHETIC RUBBER Butadiene – styrene Rubber January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 38 800px-SBRwithexplicitC.png Trans! January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 39 KRALEX® 1500 is a standard grade of styrene butadiene rubber. It is produced by a technology of cold emulsion polymerization based on soaps of rosin acids and contains 23.5% of chemically bonded styrene. It is coagulated by a system of acid and organic coagulant, does not contain extender oil and is stabilized by staining antioxidant. KRALEX® 1500 is appropriate for rubber compounds used in the production of car tires and inner tubes, conveyor belts, footwear, cables, hosepipes and various technical rubber articles. It is not approved for production of rubber articles coming into contact with foods or drinking water. KRALEX 1500001.jpg January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 40 img617.jpg Viscosity Mooney – Explanation and Measurement Mooney-mv-2000.jpg 800px-Mooney_viscometer.jpg 1.Rotor 2.Tested Material 3.Mould 4.Registration Device January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 41 Mooney viscosity rubber_compounds_CURVE GOOGLE IMAGES 0512018.jpg Mooney viscosity CURVE prevulcanization(2)GOOGLE IMAGES 05012018.jpg January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 42 The rubber compound, including the vulcanizing system, is shaped on the mill as 6–8 mm thick sheets. Round-shaped samples with 45 mm diameter are cut from the sheets. The samples are pierced in the middle in order to allow the rotor shaft to pass. Before the beginning of the measurement, the instrument is heated up to 118 degree C. After the sample is introduced, it takes a minute for the sample to reach the thermal equilibrium, and then the rotor is started. The value of Mooney viscosity decreases at the beginning, due to the decrease of the compound viscosity as temperature rises. After about 4 min, a minimum value is reached, which stays constant for a while. This value is indicated as MV. After a certain period of time, vulcanization starts and the Mooney viscosity increases. The following values are indicated on the obtained curve: minimum viscosity MV; scorch time (t5) - the time interval (measured from rotor start) corresponding to a viscosity increase of 5 Mooney units over MV, measured at rotor start. The t5 value indicates the prevulcanization tendency of the compound. The larger t5 is, the lower the prevulcanization tendency, and, therefore, the rubber compound can be more reliably processed on mill, calender or extruder. [3] vulcanization time (t35) - the time interval (measured from rotor start) corresponding to a viscosity increase of 35 units over the MV value. vulcanization index - Dt30 = t35 - t5 - provides indications about the vulcanizing ability of a rubber compound. A compound with a low vulcanization index, cures more rapidly than a compound with a higher vulcanization index. optimum vulcanization time at the experimental temperature employed (top). Modification of the NATURAL RUBBER 1 The MOST COMMON IS CHLORINATION by elementary Chlorine January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 43 img560.jpg The double Bonds are here maintained > Kept the Possibility of the Vulcanisation It is here Demonstrated at: Trans isomer = Gutta-percha Chlorinated Rubber Modification of the NATURAL RUBBER 2 & 3 The LESS COMMON PPROCEDURES January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 44 reakce přír. kaučuku s HCl.jpg chlorace & cyklizace přír. kaučuku.jpg Acid catalyzed addition of H+ on the DOUBLE BONDS, isomerisation and cyclization > CYCLORUBBER Trans! RUBBER iso-RUBBER 2 3 January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 45 Modification of the NATURAL RUBBER (NOT VULCANIZED RUBBER) a její využití Type Properties Use Chlorinated Rubber (chlorine content up to 60 % w/w) Film forming, better chemical stability than NATURAL RUBBER , decreased flammability, SOLUBILITY IN ORGANIC SOLVENTS Coating compositions (chemical works, e.g. Starch factory, Sugar factory etc.), Glues Rubber hydrochloride (modification by gaseous HCl) (chlorine content up to 35 % w/w) Film forming, better chemical stability than NATURAL RUBBER, bur worse than Chlorinated Rubber, decreased flammability, SOLUBILITY IN ORGANIC SOLVENTS Films, Sizing for Textile industry Chlorinated Rubber is probably the most important MODIFIED NATURAL RUBBER January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 46 Modification of the NATURAL RUBBER (NOT VULCANIZED RUBBER) Type Properties Use CYCLORUBBER Film forming, SOLUBILITY IN ORGANIC SOLVENTS Films, Sizing for Textile industry, paper, lacquers, glues, printing inks January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 47 Modification of the NATURAL RUBBER (NOT VULCANIZED RUBBER) What interesting did I personally Coating compositions (Starch factory in Brno town) I have worked in the Maintenance department, getting ready for the Starch season (Beginning of the Potato processing to Starch). I have painted the processing devices inside. EXPERIENCE: Hygiene problems, Vapours of Solvent, Shortage of fresh Air Vulcanized Rubber and Antiques conservator - restorer •The response need also the Subjects made of Rubber already! •My former Student turned to me for Help in his Task in the Technical Museum in Brno •PROBLEM: •Gas mask restoration dated in the 1. World war •Gas mask restoration dated in the last 30rd years January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 48 POLYTERPENES and Antiques conservator - restorer •Gutta-percha > isolation of the electric conductor > The first submarine TELEPHONE CABLE EUROPE - AMERICA •BALATA > another interesting Plant, a similar and cheaper natural material called balatá is often used in gutta-percha's place. The two materials are almost identical, and balatá is often called gutta-balatá. January 2018/4_1 NATURAL POLYMERS MU SCI 4_1 2018 49