Polymer blends and composites - compatibilization Pirjo Pietikäinen

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1 Polymer blends and composites - compatibilization Pirjo Pietikäinen

2 Classification of polymers Raw material based rganic, inorganic il based, plant based Homopolymers, copolymers Thermoplastics, thermosets, elastomers Crystalline amorphous End use applications wide variety of different kinds of materials

3 Synthetic polymers (plastics) 1.5 million tons in million tons in 2014 Polyolefins (PE and PP) > 50% Raw material from oil and gas productions Easily polymerized, cheap Chemical and corrosion resistant Non-toxic Easily thermoformed PE % 31 PP % 20 ther synthetic polymers % 49 Engineering plastics ~10 % Superior thermal and mechanical properties, also bio Expensive, *polyolefin

4 Classification Biobased Petrochemical raw mat. Renewable raw materials Biodegradable Not biodegradable Not biodegradable Biodegradable Petrochemical raw materials

5 Polymer blends and composites The other component?

6 Formation of polymer blends and composites Polymer + Polymer/reinforcing agent/filler + Compatibilizing agent + Mixing as solution in melt 9/25/2017 6

7 Blend vs. composite Polymer blend Polymer + polymer e.g. PE/PA Polymer composite Polymer + reinforcement or filler e.g. Epoxy + carbon fiber

8 Polymer composites Flexibility of matrix + stiffness of reinforcement Pros High stiffness and toughness vs. weight Chemical stability Possibility to orientate the structure Shapeability Processing of large entities (extrusion, injection molding ) Cons Poor thermal and electrical conductivity Low operating temperature of polymers Serial production not developed widely Un-standardized materials Sometimes high prizes of the materials 8

9 Polymer blends an example Polyamide 6 (PA6) Polyethylene (PE) + stiff, strong - brittle + good barrier -properties (oxygen, solvents) - sensitive to moisture + good thermal properties + tough + no water absorption or permeability - swelling by solvents - high oxygen permeability + processability + affordable HC N H n NH 2

under heating, -Combustibility These poor properties can be improved by blending

10 Polyolefins vs. engineering plastics Polyolefins suffer from -Softness -Creeping -Decreased modulus under heating, -Combustibility These poor properties can be improved by blending fillers (glass fiber, silica, CaC 3, Talc, Al(H) 3 etc.) in polyolefin These P-composites can replace engineering plastics in different kinds of applications

11 Reinforcement

12 Breaking of a composite material

13 Functionality of polymer composites Materials function together Stiffness and toughness of the fiber Flexibility of the matrix Matrix protect the fibers Enormous possibilities to develop materials.

14 Factors affecting mechanical properties of reinforced polymers Reinforcement - cut - continuous - textile concentration size shape distribution orientation Matrix - thermoplastic - thermoset Mechanical properties - static, dynamic - yielding - wear resistance Test conditions Processing - methods - conditions

distribution orientation Matrix - thermoplastic - thermoset Mechanical properties -

15 Factors affecting mechanical properties of reinforced polymers Compatibilization (coupling) Reinforcement - cut - continuous - textile concentration size shape distribution orientation Matrix - thermoplastic - thermoset Mechanical properties - static, dynamic - yielding - wear resistance Test conditions Processing - methods - conditions

16 How to select the compatibilizer /coupling agent Chemical structure of the interfaces of Polymer matrix Reinforcement/filler 9/25/

17 Miscibility, compatibility Conclusions based on the number of T m /T g detected T g / T m between that of the components Applies also to heterogeneous blends with very fine scale the number of phases observed in SEM micrographs Technologically relevant definition Components compatible if the blend exhibits an initially desirable balance of properties that doesn t deteriorate over a time equal to the useful life that is expected of articles made form the mixture Imre, artsu; Rudin, Choi 9/25/

18 Some definitions HPB homologous polymer blend Two fractions having different MW MPB miscible polymer blend PB homogeneous to the molecular level; ΔG m ΔH m 0 IPB immiscible polymer blend ΔG m ΔH m > 0 9/25/

19 Some definitions Compatible polymer blend Commercially attractive polymer mixture, homogeneous to eye, enhanced properties compared to the constituents PA - Polymer alloy IPB having modified interphase and/or morphology Compatibilization Process of modification of interfacial properties if IPB Polymer alloy EPB - Engineering polymer blend A PB or PA either containing or having properties of EP 9/25/

20 Compatibilizers Provide miscibility or compatibility Immiscible or partially immiscible materials Helps of forming a homogenous product Reduce interfacial tension Concentrated at phase boundaries Reactive Chemical reactions with materials Nonreactive Physical effects Charraher 9/25/

21 Why compatibilization? 1. To reduce interphase tension engendering finer dispersion 2. To make certain that the morphology generated during the mixing stage will not be destroyed during high stress and strain forming 3. To enhance adhesion between the phases in the solid state, facilitating the stress transfer improving the mechanical properties of the product Utracki, /25/

22 How compatibilization? 1. Addition of a small quantity of a third component that is miscible with both phases (covalent) 2. Addition of a copolymer whose one part is miscible with one phase and other with another phase (e.g wt%, usually blockcopolymer, seldom graft) 3. Addition of a large amount, usually wt% copolymer having multipurpose nature (e.g. + impact modifier) 4. Using chemical reactants in compounding (in situ formation of compatibilizers) Utracki, /25/

23 Compatibilization by addition Addition of a third component Block or graft copolymer Segments having segments having specific interactions with main polymeric components viz. H-bonding, dipole-dipole Addition of a third polymer (migrates to interphase, mod. interphase) Thermodynamical requirement Concentration on the interphase Dissolves in both phases (micelle formation) May affect the flow behavior Utracki, /25/

24 Designing compatibilizers Maximization of miscibility Minimization MW just to entanglement MW for each interacting block Minimization copolymer concentration in the blend wt% sufficient 9/25/

25 Reactive compatibilization Today dominant method = specific chemical reaction between two polymeric components during mechanical blending Interfacial agent produced in situ The highest MW copolymer is the most desirable A thick interphase with stabile morphology Challenge: increased viscosity Usually block and graft copolymers are formed Utracki,

26 Requirements for reactive compatibilization Sufficient dispersive and distributive mixing (renewal of the interface) Presence of reactive functionality capable to react across the interface Sufficient reaction rate sufficient amount of compatibilizing copolymer within the residence time of the processing unit Stability of the chemical structure 9/25/

PE/PA6 (80/20) Smaller particle size and increased

27 Example of compatibilization Reduction of surface tension between phases Addition of a compatibilizer PE/PA6 (80/20) Smaller particle size and increased adhesion Desired property combination +SEBS-g-XA 10%

28 Example of compatibilization N CH PE NH 2 NH 2 CH PA6 CH PE PE NH 2 N

29 Example of compatibilization NH 2 CH CH PA6 NH 2 N H H N N H PE PE PE

30 What has compatibilization to do with recycling of polymers?

31 Journal article to study What matrix? What blended/mixed in? Compatibilization? Results shortly Challenges? What gained? 9/25/

32 Reactive vs. non reactive compatibilizer REACTIVE (black marks) PLA/starch 55/45 PLA/poly(propylene carbonate) 70/30 NN-REACTIVE (white marks) PLA/PE 80/20 PLA/PCL 80/20 PLA/PCL 50/50 Imre & Pukanzky 2013

33 Effect of compatibilization White mark PP/TPS (thermoplastic starch) Black mark PP/TPS/MAPP Imre & Pukanszky

34 Particle size White marks Physical blend PLA/PU Black marks 9/25/2017 Reactor blend PLA-g-PU (isocyanate) 34 Imre & Pukanszky 2013

35 Preparation of compatibilizers Block copolymers Diblock most effective Exist for small number of polymer pairs Graft copolymers Possible also in situ Step polymers Functionalities of chain ends used e.g. polyamide (amino and carb.acid groups) Addition polymers Copolymerization or grafting Important to have enough functionality vs. reaction time

36 Grafting vs. copolymerization CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 kat. CH 2 CH 2 kat. MA H H

37 Grafting vs. copolymerization Post modification Side reactions crosslinking degradation reactive C=C MAH, acrylates, GMA, XA During polymerizatrion vinylic C=C Shielding of the functionality -H, -CH, -NHR, - CNHR, -CR

38 Grafting Matrix Monomer Peroxide Polymer blends Impregnation Processing Purification IR-analysis NMR-analysis Films Dissolution

39 Effects of compatibilization 39

40 PE/PA NB neat PE PE/PA6 (40/60) + 10% PE-co-H neat PA6 Vetokimmomoduuli Tensile modulus Yield Myötölujuus strength Elongation Venymä at break Charpy- Unnotched iskulujuus Charpy Charpy- Notched iskulujuus Charpy MPa MPa MPa %% (loveamaton) kj/m 2 (lovi-isku) kj/m 2 kj/m 2 kj/m 2 Young s modulus Strength Elongation Impact strength

41 PE/PA6 PE/PA6 +PE-g-XA +SEBS-g-XA +PE-co-H +E/BA/MAH Vetokimmomoduuli (MPa) Vetolujuus (MPa) Venymä (%) Iskulujuus, loveamaton (kj/m2) Iskulujuus, lovettu (kj/m2) Young s modulus Strength Elongation Impact strength

42 PE/PA6 PE/PA6 40/60 +SEBS-g-XA 10% +PE-co-H 10% +E/BA/MAH 10% x 2 000

43 PP/PA6 PP/PA6 (70/30) +PP-g-XA +SEBS-g-XA +PP-co-H +(E/BA/MAH) +PP-g-MAH Vetokimmomoduuli (MPa) Vetolujuus (MPa) Venymä (%) Iskulujuus, loveamaton (kj/m2) Iskulujuus, lovettu (kj/m2) Young s modulus Strength Elongation Impact strength

44 PP/PA6 PP/PA6 70/30 +SEBS-g-XA 10% +E/BA/MAH 10% +PE-co-H 10%

aggregated in polyolefin matrix H H H H X H X CH 2 CH 2 CH 2 CH

45 Challenges in polyolefin composite technology Mineral fillers detach from the polyolefin matrix Mineral fillers remain aggregated in polyolefin matrix H H H H X H X CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH2 CH2 CH2 CH2 2 CH2 CH2 CH2 CH2

46 Peroxide grafting in extruder Unwanted side reactions, e.g. chain scission CH 2 CH 2 2 CH 2 CH 2 CH 2 2 CH CH2 CH CH 2 CH 2 CH 2 2 H 2 C CH X H 2 C CH X H 2 C CH X

47 Direct copolymerization in pipe-line reactor Drastic conditions (300 C, 2500 bar)!! X CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH 2 CH2 2 CH2 2 CH2 2 CH2 2 CH2 2 CH2 2

48 Direct copolymerization in low pressure Tolerable reaction conditions (<100 C, <10 bar) Requires co-ordination catalyst (Metallocene or Z-N complex) Metallocenes tolerate Lewis-basics (X=, N) to some extent, but the deactivation remains still a big problem H 2 C CH2 H 2C CH 2 The polymerization of Lewis acids (X= Si, B) proceeds normally without catalyst deactivation Cl Zr Cl Activation Zr CH 3 CH 2 H 2 C H 2 C CH2 CH 2 Zr H 2C CH 2 X CH 2 H 2C CH 2 Zr X CH 2 H 2C X CH Zr H 2C CH 2 H 2 C CH 2 H 2 C CH 2

49 Silane functionalized polyolefins The influence of the silane functionalized polyolefins on the mechanical properties of the P-composites were studied P-composite without the compatibilizer P-composite with the compatibilizer

50 PE/ATH (fire retardant) H ATH H H H H H C C C C C C ATH C C C C C ATH C

51 PE/ATH PE/ATH 60/40 PE/ATH(SA) 60/40 PE/ATH/(E/BA/MAH) 50/40/10 PE/ATH/(PE-co-H1) 50/40/10 x

52 PE/ATH and PE/MH Vetokimmomoduuli (MPa Vetolujuus (MPa) 0 PE +ATH +MH +ATH(SA) +MH(SA) +ATH+E/BA/MAH +MH+E/BA/MAH +ATH+PE-co-H1 +MH+PE-co-H3 +ATH+PE-co-CH1 +MH+PE-co-CH2 +ATH+PE-g-XA +MH+PE-g-XA 0

53 PE/ATH and PE/MH Iskulujuus (kj/m 2 ) Venymä ( % ) MH+PE-g-XA +ATH+PE-g-XA +MH+PE-co-CH2 +ATH+PE-co-CH1 +MH+PE-co-H3 +ATH+PE-co-H1 +MH+E/BA/MAH +ATH+E/BA/MAH +MH(SA) +ATH(SA) +MH +ATH PE

54 Cellulose hydrophobicity with amphiphilic copolymers

55 Why blends? Products Developing materials with full set of desired properties Extending engineering resins properties by diluting them with low-cost commodity polymers Improving specific property e.g. rigidity, flammability, abrasion resistance Adjusting the material performance to fit customers specifications at the lowest price Recycling industrial and/or municipal waste 9/25/

56 Why blends? Producers Better processability improved product uniformity and scrap reduction Product tailorability to specific customer needs customer satisfaction Quick formulation changes plant flexibility and high productivity Reduces the number of grades needed in manufacture savings in capital investment and storage Recyclability of blends achieved by control of morphology improved economy 9/25/

57 Literature examples Rudin, A., Choi, P., The elements of polymer science and engineering, 3rd ed., Elesvier, 2012, Utracki, L.A., Commercial polymer blends, Chapmen&Hall, 1998, 258s. Utracki, L.A., Polymer alloys and blends, Thermodynamics and rheology, Hanser, 1989, 356 s. Hippi, U., Novel functionalized polyolefins as compatibilizers in polyolefin/polyamide 6 blends and polyethylene/metal hydroxide composites, Doctoral dissertation, Helsinki university of technology, 2005 Lipponen, S., Silane functionalized polyolefins via metallocene catalysis; Synthesis and use in polyolefin composites, Doctoral dissertation, Helsinki university of technology, Utracki, L.A., Compatibilization of polymer blends, The Canadian journal of chemical engineering, 80 (2001) Imre, B. and Pukanszky, B., Compatibilization of bio-based biodegradable polymer blends, European polymer journal, 49 (2103), /25/

Sustainability in a Materials context Natural resources Sun Moon Earth Energy Conversion Fossil

energy Materials 2% of all biomass Biomass Transport Industry Buildings ther 23% 35% 33% 8%

End of life Material efficiency Conserve resources Material stock Goods Services GDP Landfill

58 Sustainability in a Materials context Natural resources Sun Moon Earth Energy Conversion Fossil fuels Sun Fossil fuels Fertilizers Land Water & Minerals Air Conversion Useful energy 21% of all energy Materials 2% of all biomass Biomass Transport Industry Buildings ther 23% 35% 33% 8% Energy efficiency Conserve energy Carbon-free energy Re-use, recycle Combustion Manufacture Use End of life Material efficiency Conserve resources Material stock Goods Services GDP Landfill Material stock Food Bio-fuels Feedstock ther Bio efficiency Recycled by nature Conserve habitat Bio-diversity

Lecture No. (1) Introduction of Polymers

Lecture No. (1) Introduction of Polymers Polymer Structure Polymers are found in nature as proteins, cellulose, silk or synthesized like polyethylene, polystyrene and nylon. Some natural polymers can also