Тема 2 1 Основні хромофорні групи 2

Тема 2

1. Основні хромофорні групи. 2. Особливості спектрів поглинання полімерів. 3. Застосування для аналітичних цілей.

Основні хромофорні групи • Парафіни 100 -200 нм * • Насичені молекули, що містять ауксохроми • Ізольована етиленова група 190 нм ( max= 10 000) * Етилен: 180 нм, 210 нм Сполука max, нм CH 4 125 - * C 2 H 5 135 - * H 2 O 167 CH 3 OH 183 max Тип переходу 7000 n * 500 n * (CH 3)2 O 185 n * CH 3 NH 2 213 n * CH 3 Cl n * 173

Основні хромофорні групи Замісник NR 2 OR SR Cl CH 3 Зсув, нм 40 30 45 5 5 • Дієни прості похідні бутадієна-1, 3 217 -230 нм ( max= 20 000) Сполука CH 2=CH-CH=CH 2 max, нм max 217 CH 2=C(CH 3)-CH=CH 2 220 -CH 3 CH=CH-CH 3 227 21000 23000

Основні хромофорні групи • Карбонільні сполуки: 217 -230 нм ( max= 20 000) Ацетон 280, 190, 150 нм Ацетофенон 325 нм Бензальдегід 325 нм Бензофенон 348 нм

Основні хромофорні групи • , -ненасичені карбонільні сполуки: Інтенсивна 220 -260 нм ( max~10 000) малоінтенсивна 320 нм ( max<100)

Супряжені системи Хромофорна система Смуга * max, нм max С=С-С=С 217 21 000 С=С-С≡С 219 6 500 С=С-С=О 217 16 000 С=С-С=N 220 23 000 С=С-C=C 258 35 000 С=С-С≡С-C=C 257 17 000 С=С-C=O 263 27 000

Основні хромофорні групи R RC 6 H 5 200 nm 260 nm max, нм max H 203, 5 7400 254 204 CH 3 206, 5 7000 261 225 OH 210, 5 6200 270 1450 CH=CH 2 244 12000 282 450 C≡CH 236 12 500 278 650 COCH 3

Розділення хромофорів

Особливості спектрів поглинання полімерів • -[CF 2 -CF 2]-

Визначення якості сировини

Additives in PP • Anti-oxidants and neutralizers • Nucleants • Antistatics • Demoulding Antistatics • Miscellaneous 18

Antioxidants and Acid Scavengers • primary antioxidants = radical scavenger, e. g. HP 136, Irganox 1010 • secondary antioxidants = decomposer of Hydroper -oxids, e. g. Irgafos 168, a phosphit for processing protection or thioester for long term heat stabilization • acid scavenger: Calcium or Zinc stearate for corrosion protection Ca(O 2 C 18 H 35)2 O HO CH 2 C Irganox 1010 4 O O H HP 136 O P 3 Irgafos 168

Antistatic Agents Schematic representation of the effect of internal antistatic agents H 2 O H 2 O H 2 O H 2 O H 2 O hydrophilic head, e. g. COOR hydrophobic tail, e. g. alkyl-chain

Antistatic Agents o glycerol monoesters, e. g. glycerol monostearate, GMS: GMS 95 or GMS 55 respectively which are mixtures of glycerolstearates (mono, di, tri) with approximately 95 % or 55 % GMS respectively. o glycerol monolaurate o ethoxylated secondary amines

Nucleating Agents Types of nucleating agent Inorganic: talc; benzoate & phosphate salts Organic: sorbitol derivatives R 2 O R 1 CH 2 R 2 HC O HC CH CH R 1 O HC-OH CH 2 -OH Factors affecting the transparency of polypropylene: Degree of crystallinity; crystal structure; crystallite size; Relative refractive indices of matrix/dispersed phase; particle size distribution of dispersed phase

Crystallisation of PP Crystallized with nucleating agent Crystallized without nucleating agent Smaller spherulites results in: Higher Tc, Lower cycle times due to shorter cooling times Higher rigidity, thinner sections possible and ejection easier Superior transparency; dimensions of spherulties smaller, thereby causing less light scattering Higher shrinkage; parts can stick to core therefore making ejection more difficult 23

Stabilization Neutralizers; thermal- and processing stabilizers Practical benefit - prevention of polymer degradation during storage & processing plus corrosion of mould and dies Neutralizers – PP contains small amounts of catalyst residues of acidic nature, thus acid scavengers (neutralizers) are added to prevent damage to polymer, moulds and dies. Anti-acids include metallic stearates, Ca- and Zn. Oxides Anti-Oxidants – Degradation occurs mainly in terms of chain scission due to oxidation (from process conditions) or shear (from screw) – to prevent this, primary (phenolics) and secondary antioxidants A. O. (phosphites, phosphonites) are added – Primary A. O function as radical scavengers – Secondary A. O function as synergistic players with the primary A. O. and are normally used in A. O. blends 24

Antistatics Practical benefit - no dust pick-up on items & improving demoulding during processing PP is a very good insulator and hence tends to accumulate static charges Antistatics used: hydrophilic molecules which have a limited solubility like glycerol monostearate (GMS) and ethoxylated amines These migrate to the surface and absorb moisture which provides some conductivity Overdosing results in aesthetic and post production process problems 25

Nucleation The principle is to influence microstructure by offering an additional amount of nuclei. The nucleating agent acts as a crystallization initiator – normally a nucleated PP is stiffer due to higher level of crystallinity and thus shows a higher DSC crystallization temperature – Materials typically used are • Melt sensitive nucleants like sorbitol-based nucleants. Resin is clearer due to smaller spherulites, good dispersion necessary. These types of nucleants are also known as clarifiers • Melt insensitive: like benzoate salts or talc which increase the stiffness but do not improve the optical properties 26

Miscellaneous Fillers such as talc, calcium carbonate, clay (глина), mica (слюда) Pigments Slip additives (Erucamide, Oleamide) (добавки против слипания) Anti-block (Ca. CO 3, Silica) (антибликовые добавки – блокировка адгезии слоёв пленки) Anti-UV (e. g. HALS) hindered amine light stabilisers (HALS) 27

Characterization of PP (or PE) (Density of PP = 0. 90 ± 0. 01 gcm-3 does not change) Analytical Thermal Rheological Optical Mechanical Chemical Resistance Barrier Properties 28

Analytical Methods HPLC (High Performance Liquid Chromatography) – for quantitative determination of Additives GPC (Gel Permeation Chromatography) – for determination of MWD NMR (Nuclear Magnetic Resonance Spectroscopy) – determination of Co-monomer (C 2) content IR and Raman Spectroscopy – functional groups (“molecules”) e. g. polymer types, qualitative determination of additives, determination of fillers Micro Probe (SEM) – chemical elements e. g. in Pigments or inorganic components (metal contamination!) 29

Thermal Behaviour DSC (Differential Scanning Calorimeter) – melting temperature Tm – crystallization temperature Tc – Enthalpy DH gives an indication of crystallinity Vicat softening point (ISO 306) – penetration of a needle (1 mm 2) – T is increased with 50 Kh-1, – Test is complete when needle has penetrated 1 mm – values reported in °C for a certain load (A and B) HDT (Heat Deflection Temperature ISO R 75) – flexural test – T increase 2 Kmin -1 – Test is done when certain bending has happened – values reported in °C for a certain load (A and B) 30

Добавки в полімерах • Пластифікатори • Стабілізатори

Добавки в полімерах • Стабілізатори

Добавки в полімерах (стабілізатори)

Добавки в полімерах (пластифікатори) 276 230

Вивчення хімічних реакцій в полімерах

Вивчення хімічних реакцій в полімерах

Вивчення хімічних реакцій в полімерах

Вивчення хімічних реакцій в полімерах