R2 UNIVERSITY F PANNNNIA INSTITUTINAL DEPARTMENT F ML HYDRCARBN AND CAL PRCESSING CSILLA VARGA M.SC. IN CHEMICAL ENGINEERING PRDUCTIN AND INVESTIGATIN F CMPATIBILIZING ADDITIVES FR PLYMER CMPSITES Theses of PhD dissertation SUPERVISR: PRF. LÁSZLÓ BARTHA R 1 CH 2 CH CH 2 CH 2 CH CH 2 H HN H N R 2 H 2 C a CH 2 b k CH l 2 a m CH 2 b n abszorbancia 3500 3000 2500 2000 1500 1000 0.00 0.10 0.00 0.10 3500 3000 2500 2000 hullámszám, cm -1 1500 1000 A4 A8 Veszprém 2010
1. Introduction In recent days polymer composites have been applied in increasing quantities in a lot of fields of activities. They are used in the everyday utensils and devices, in structural materials and in vehicles. Generally composites consist of several phases and interphases exist between them playing an important role in the characteristics of the end product besides the properties of the raw materials. For satisfaction of the new requirements arising almost every day developments of new materials and technologies are needed in many cases by which introduction the importance of the knowledge and the usage of the interfacial interactions is getting higher and higher. Interfaces and the phases between them are playing a similarly important role in each composite and the surface modification should be chosen based on the purpose and on the properties of the systems. There are no generally applicable materials and additives which are efficient either in fibre reinforced composites, in polymer blends or in nanocomposites. The composite elements determine the modification technique of the interface either. If mechanical properties of fibre reinforced composites are to be improved strong chemical interaction is needed between the fibres and the matrix because efficient load transfer can be achieved only by that way. In that case coupling agent is needed for establishing chemical bonds. In carbon nanotubes containing composites not only the proper interaction is to be established between the nanotubes and the matrix but also the strong ability of the nanotubes for agglomeration should be decreased. Silane type coupling agents and maleic-anhydride grafted polymers are often applied but in most cases they are used in the different composites upon the previous successful results and not taking care about the chemical composition of the parts. However, the common features of the interfacial interactions in heterogeneous systems are worth to consider. The new expectations against the structural materials could be achieved not only by the development of new composites but also by the further development of the existing ones. For that the rethinking of the existing results and experiences and the revealing of the possible ways or methods considered previously unworkable is needed. The area of the conventional fibre reinforced thermosets is one of them. In the last years the interest in the glass fibre reinforced thermosets decreased probably due to the detailed study of the effects of the coupling agents and the mechanisms of the coupling and the sizings 1
containing silanes function also properly in glass fibre containing systems. As the prices of the carbon fibres haven t decreased so much as it was expected the interest in the carbon fibre reinforced composites applied mainly in the aircraft and space areas also decreased. Researches have been continued, however, by lower dynamism since the further development of the existing methods and technologies could also be successful. If for improving the mechanical properties more efficient additives can be applied, the similar technical requirements can be achieved by application of lower amounts of raw materials. 2. bjectives The main aims of my experimental work have been the improvement of the mechanical properties of different fibre reinforced composites by application of new types of additive package. I have studied the application possibilities of those additives, the advantageous concentrations, the relationships between the composition of the additives and the mechanical properties of the composites containing the abovementioned additives, and the mechanisms of the improving effects. For carbon fibre reinforced polyolefins olefin-maleic-anhydride copolymer based coupling agents have been applied. The effects of the composition of the additives and the fibre content on the mechanical properties and on the fibre/matrix interaction have been studied. A new impregnation method for carbon fibres have also been investigated for production of long carbon fibre reinforced commodity thermoplastics by injection moulding process. By modification of the polymer chains and application of styrene comonomer, new composition of terpolymer additives have been produced for glass fibre reinforced thermoset composites. The effects of the changes in the matrix type and the orientation of the reinforcements on the mechanical properties in additive treated glass fibre containing polyester and vinyl-ester composites have been studied. The effects of the modification of the additives have been investigated by the mechanical properties of the composites and the properties of the fibre/matrix interface in them. Determination of the acid and saponification numbers of the produced additives has difficulties because of the carboxyl-groups in different chemical environments having 2
different behaviour during the titration. Acid and saponification numbers determined by titration could be misleading because it can not give information about the ratios of the derivatives inside the additive. The impropriety of the titration can be sometimes caused by the limited solubility of the polymers which can make the stoichiometric reactions be unsure or even hindered. Besides during the standardized titration such indicating material has to be used which can only indicate the reaction of the first carboxyl group from the anhydride rings in minor acidic ph range. The second neutralisation reaction can be conducted only in alkaline medium and the low reacting ability of the carboxylgroups from the anhydride rings and therefore, the swing-over point could be determined more difficult. For determining the composition of the additives containing carboxyl-groups in different chemical environments a new evaluating method has been applied based on the integration areas under the absorption peaks of the carbonyl-groups in the FT-IR spectra of the coupling agents, then the acid and saponification numbers of the additives have been determined according to the reactions during titration and the ratios of the derivatives from the FT-IR estimation. 3. Methods Analytical methods: o Determination of acid number (special standard) o Determination of saponification number (MSZ IS 6293:1994) Spectroscopic method: o FT-IR Spectroscopy o Scanning Electron Microscopy o FT-IR Imaging Spectroscopy o FT-Raman Microscopy Mechanical tests: o Tensile test (MSZ EN IS 527-1-4:1999) o Flexure test (MSZ EN IS 178:2001) o Charpy impact test (IS 179-2:2000) o Determination of fibre content (MSZ EN IS 3451-1:1999) 3
4. New scientific results 1. The author has developed a new evaluating method based on the FT-IR spectra of the coupling agents for determination the composition of the additives containing carboxylgroups in different chemical environments more exactly than sofar. a) Acid numbers calculated from the integration areas under the carbonyl absorption peaks by integration method B differed with ±14,8% (R 2 =0,74), and the acid numbers determined by the standardized titration method varied with ±31,8% (R 2 =0,43) from the theoretical acid numbers calculated from the amount of the reagents. According to the calculations from the FT-IR spectra the composition of the product can be estimated more exactly than with the conventional methods. b) Saponification numbers calculated from the integration areas under the carbonyl absorption peaks by integration method A differed with ±8,7% (R 2 =0,87), and the saponification numbers determined by the standardized titration method varied with ±16,5% (R 2 =0,79) from the theoretical saponification numbers calculated from the amount of the reagents. 2. The author has produced efficient new type of coupling agents containing ester, esteramide and imide derivatives from olefin-maleic-anhydride copolymers for treating the surface of the carbon fibres. a) The impregnation method of the carbon fibres and the type of composite processing has been established to significantly influence the average fibre length and the fibre length distribution characteristic for the polyolefin composites. Average fibre length for the extrusion method has been demonstrated to be under 500 μms, while the highest amount, at least 50% of the fibres has been proven to be over 500 μms for composites produced by the masterbatch method, so therefore, only the masterbatch method can be applied for production of long (0.8-2.8 mm) carbon fibre reinforced polyolefin composites. b) Among the linear C 12-22 α-alcohols application of hexadecanol has been determined to be optimal in the coupling agents for PP composites. c) Increasing the carbon number of the amine component from 4 to 12 made the mechanical properties decrease. 4
d) Effectiveness of the coupling agents has increased in the LDPE<LLDPE<HDPE<PP order. According to that long chain branches in the polyolefin have not been preferable for the additive/matrix interaction. 3. The author has produced efficient new type of coupling agents containing ester, esteramide and imide derivatives from olefin-maleic-anhydride-styrene terpolymers for treatment of the surface of glass fibres. a) The strength of the additive/fibre interaction, therefore, the mechanical properties of the glass fibre reinforced polyester composites have been proven to be dependent on the ratio of the different derivatives (ester, ester-amide, imide and anhydriderings) in the additives that can be influenced by the type of the alcohol reagent. For advantageous fibre/matrix interaction the additives should contain ester derivative for which at least dodecanol reagent is needed. b) The strong additive/fibre interaction has been proven not to be advantageous for improving the mechanical properties of vinyl-ester composites. Glass fibres became apolar due to the modification of the fibres with the additives, therefore, deteriorating the interaction between the polar groups of the vinyl-ester and the glass fibres. c) Smoother additive-sizing has been proven to be established on the fibre surface in case of application of glass woven [0/90 ] fabric, therefore, higher effects could be realized in the mechanical properties of the polyester composites than with chopped fibre mats. 4. The author has demonstrated that the new olefin-maleic-anhydride copolymer based coupling agents successfully applied for treatment of carbon fibres are applicable for treating the surface of the carbon nanotubes either. a) The impregnation technique of the carbon nanotubes has been proven to be determining for improving the mechanical properties of the carbon nanotube containing PP. According to SEM graphs the CNTs have been broken if mixing is applied during the impregnation, but modification of the impregnation method, so avoiding mixing, made the CNTs be visible, so no breakage has occurred. b) Yield strength of the rubber with higher, 13.9 MPa yield strength has been indicated to decrease significantly, by 23%, during high fatigue stresses (for 500 cycles) while the yield strength of the surface treated CNT containing rubber do not change. Yield and fatigue yield strengths of the rubber with lower strength (yield 5
strength: 8.6MPa) have been proven to be significantly improved by treating the CNTs while density of the products increased only minimally. c) Coupling agent produced with dodecanol and n-butyl-amine has been determined to be successfully applicable for improving the compatibility of the CNT surface and the rubber because of the increase of the yield strength of the base rubber by 35% due to the application of the additive. 6
5. Application areas Upon the relationships between the chemical composition of the coupling agents and their effects the possible concentration range, application methods and the level of the improvements have been determined in different fibre reinforced polymer composites. In carbon fibre reinforced polyolefin composites the effective impregnation of the fibres have been solved for which such new additives have been produced that can be easily applied on the fibre surface and can improve the compatibility of the fibres and the matrix either, because the maleic-anhydride grafted polymers applied widely until recent days Long carbon fibre reinforced geogrid are not effective enough. From granulates long carbon fibre reinforced composites can be produced either by extrusion (e.g. geogrid) or by injection moulding. The further importance of the impregnation method and the additives can be realized in the production of long carbon fibre reinforced commodity thermoplastics even by conventional injection moulding machines and therefore, there is no need for a new type of injection moulding machine. 7
Publications Journal papers 1. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Hosszú szénszállal erősített műanyag kompozitok mechanikai tulajdonságai, Műanyag és Gumi 2007 (44), 2, 83-87. 2. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Hosszú szénszállal erősített PP, HDPE és EVA kompozitok, Műanyag és Gumi 2007 (44), 5, 195-202. 3. Varga Cs., Miskolczi N., Bartha L., Lipóczi G., Falussy L.: Szálerősített műanyag kompozitok tulajdonságainak javítása, Műanyag és Gumi 2008 (45), 4, 148-152. 4. Cs. Varga, N. Miskolczi, L. Bartha, G. Lipóczi, L. Falussy: Improving the compatibility of man-made fibre reinforced composites, Hungarian Journal of Industrial Chemistry 2008 (36), 1-2, 137-142. 5. Miskolczi N., Varga Cs., Bartha L.: Gumiőrlemények elemösszetételének meghatározása energiadiszperzív röntgenfluoreszcens módszerrel, Műanyag és Gumi 2009 (46), 6, 235-239. 6. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Szénszállal erősített polipropilén kompozitok tulajdonságainak javítása a szálak felületének módosításával, Műanyag és Gumi 2009 (46), 10, 392-396. 7. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Kapcsoló ágenssel módosított szénszállal erősített polikarbonát kompozitok mechanikai tulajdonságainak vizsgálata Műanyag és Gumi 2009 (46), 12, 466-468. 8. Cs. Varga, N. Miskolczi, L. Bartha, G. Lipóczi: Improving the mechanical properties of glass fibre reinforced polyester composites by modification of fibre surface, Materials and Design 2010 (31), 1, 185-193. 9. Varga Cs., Szakács H., Miskolczi N., Bartha L.: Kapcsoló ágensek alkalmazása különböző szálerősítésű kompozitokban és polimer blendekben I. Műanyag és Gumi 2010 (47), 10, 388-392. 10. Cs. Varga, N. Miskolczi, L. Bartha, L. Palotás: Improving the mechanical properties of rubbers by introducing recycled rubber or different types of fillers into the original mixture Global Nest Journal 2010, megjelenés alatt 11. Cs. Varga, N. Miskolczi, H. Szakács, G. Lipóczi: Effects of industrial scale production on the chemical composition of novel coupling agents and its relationship to the mechanical properties of chopped glass fibre mat reinforced thermoset composites, Materials and Design 2011 (32), 1, 12-20. 12. A. Szentes, G. Horváth, L. Bartha, Cs. Varga, J. Szél, H. Haspel: Mechanical properties of polypropylene/multiwalled carbon nanotube composites, Hungarian Journal of Industrial Chemistry, megjelenés alatt. Patent Polyfunctional compatibilizing additive package of plastic and rubber composites and method of making the same (P0700680) 8
Book chapter in English Cs. Varga: Glass fibres: Chemistry, properties and uses, Nova Publisher, megjelenés alatt. Conference papers 1. Falussy L., Varga Cs.: Szénszál erősítésű hőre lágyuló műanyagok alkalmazási lehetőségei, Mechanoplast 2007-XV. Műanyagok műszaki alkalmazása és feldolgozástechnológiája konferencia, Gyula, 2007. március 20-22. 2. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Hosszú szénszállal erősített műanyagkompozitok mechanikai tulajdonságai, Műszaki Kémiai Napok 07, Veszprém, 2007. április 25-27. 3. Cs. Varga, N. Miskolczi, L. Bartha: Mechanical properties of fiber reinforced polyester composites 3 rd China-Europe Symposium on processing and properties of reinforced polymers, Budapest, 11-15 June 2007 (poszter). 4. Varga Cs., Miskolczi N., Bartha L.: Szálerősítésű műanyagkompozitok, Pannon Tudományos Nap, Nagykanizsa, 2007. október 10. 5. Varga Cs., Miskolczi N., Bartha L.: Szálerősítésű hőre keményedő kompozitok, XIII. Nemzetközi Vegyészkonferencia, Kolozsvár, 2007. november 8-11. 6. Varga Cs., Miskolczi N., Bartha L., Lipóczi G., Győri M., Falussy L.: Mesterséges szállal erősített kompozitok összeférhetőségének javítása, Műszaki Kémiai Napok 08, Veszprém, 2008. április 22-24. 7. Varga Cs., Miskolczi N., Bartha L., Lipóczi G., Falussy L.: Mesterséges szállal erősített hőre lágyuló és keményedő kompozitok tulajdonságainak javítása Erősített Műanyagok 2008 Nemzetközi Balaton Konferencia, Keszthely, 2008. május 20-22. 8. Cs. Varga, N. Miskolczi, L. Bartha, G. Lipóczi, M. Győri: Improved mechanical properties of compatibilizer treated chopped glass fibre mat and glass woven [0/90 ] fabric reinforced ester based composites 13 th European Conference on Composite Materials, Stockholm, 2-5 June 2008. 9. Cs. Varga, N. Miskolczi, L. Bartha, L. Falussy: Mechanical properties of long fibre reinforced composites Polymer Processing Society 24 th Annual Meeting, Salerno, 15-19 June 2008 (poszter). 10. Cs. Varga, N. Miskolczi, L. Bartha, G. Lipóczi, M. Győri: Effects of coupling agents on the mechanical properties of glass woven [0/90 ] fabric composites and glass woven [0/90 ] fabric/carbon woven fabric reinforced thermoset hybrid composites Fifth International Conference on Polymer Modification, Degradation and Stabilization (MoDeSt 2008), Liėge, 8-12 Sep 2008 (poszter). 11. Cs. Varga, N. Miskolczi, L. Bartha, L. Falussy: Effects of coupling agents on the mechanical properties of carbon fibre reinforced thermoplastic composites Interfaces 08, Sopron, 2008. szeptember 24-26. 12. Varga Cs.: Mesterséges szállal erősített hőre keményedő kompozitok összeférhetőségi problémáinak kezelése, PhD hallgatók Anyagtudományi Napja, Veszprém, 2008. november 27. 9
13. Varga Cs., Miskolczi N., Bartha L., Falussy L.: Hosszú szénszállal erősített hőre lágyuló műanyagok összeférhetőségi problémáinak kezelése, Mechanoplast 2009- XVII. Műanyagok műszaki alkalmazása és feldolgozás-technológiája konferencia, Balatonaliga, 2009. március 17-19. 14. Varga Cs., Miskolczi N., Bartha L., Lipóczi G.: Üvegszál paplannal erősített észter alapú kompozitok mechanikai tulajdonságainak és reprodukálhatóságának vizsgálata, Műszaki Kémiai Napok 09, Veszprém, 2009. április 21-23. 15. Nagy P., Varga Cs., Miskolczi N., Bartha L., Lipóczi G.: Észter alapú hibrid kompozitok mechanikai tulajdonságainak vizsgálata, Műszaki Kémiai Napok 09, Veszprém, 2009. április 21-23. 16. Szentes A., Horváth G., Varga Cs., Bartha L.: Szén nanocső/polimer kompozitok előállítása és mechanikai tulajdonságai, Műszaki Kémiai Napok 09, Veszprém, 2009. április 21-23. 17. Cs. Varga, A. Lengyel, L. Bartha, N. Miskolczi, L. Falussy: Improving the mechanical properties of PBT blends for its recycling for production of parts of pipe systems European Polymer Congress 2009 (EPF 09), Graz, 12-17 July 2009 (poszter). 18. A. Szentes, G. Horváth, L. Bartha, Cs. Varga, J. Szél, H. Haspel: Electric and thermal properties of compatibilized MWCNT/polypropylene composites International Conference on Carbon Nanostructured Materials (Cnano 09), Santorini, 3-9 Sep 2009 (poszter). 19. Cs. Varga, N. Miskolczi, L. Bartha, L. Palotás: Improving the mechanical properties of rubbers by introducing recycled rubber or different types of fillers into the original mixture 11 th International Conference on Environmental Science and Technology, Chania, 3-5 Sep 2009. 20. Szentes A., Horváth G., Varga Cs., Haspel H.: Kompatibilizált MWCNT/polipropilén kompozitok fajlagos ellenállás vizsgálata XV. Fiatal Műszakiak Tudományos Ülésszaka, Kolozsvár, 2010. március 25-26. 21. Szentes A., Horváth G., Varga Cs., Bartha L.: Kompatibilizált szén nanocső/polipropilén kompozitok vizsgálata, Műszaki Kémiai Napok 10, Veszprém, 2010. április 27-29. 22. Cs. Varga, N. Miskolczi, L. Bartha, L. Falussy: Newly developed grafted polymer type coupling agents and impregnation technique for carbon fibre reinforced polyethylene composites 14 th European Conference on Composite Materials, Budapest, 7-11 June 2010. 23. N. Miskolczi, Cs. Varga, H. Szakács, V. Sedlařík, T. Kitano, A. Gregorova, M. Mozetic, U. Cvelbar: Compatibilization of polyamide 6 and polylactic acid based resin for medical applications by polyalkenyl-poly-maleic-anhydride based derivates Polymer Processing Society 26 th Annual Meeting (PPS26), Banff, 4-8 July 2010. 24. Cs. Varga, L. Bartha, N. Miskolczi, L. Falussy: Novel coupling agents for carbon fibre reinforced composites Polymer Processing Society 26 th Annual Meeting (PPS26), Banff, 4-8 July 2010 (poszter). 25. Nagy R., Varga Cs., Bartha L.: Műanyag kompatibilizáló adalékok gélkromatográfiás vizsgálata MBILITÁS és KÖRNYEZET: a járműipar kihívásai az energetika, a szerkezeti anyagok és a környezeti kutatások területén Veszprém, 2010. augusztus 23-25. 10
26. Cs. Varga, H. Szakács, N. Miskolczi, V. Sedlařík, M. Mozetic, G. Lipóczi: Polyalkenil-poly(maleic-anhydride) and polyalkenil-poly(maleic-anhydride-styrene) based coupling agents for different types of fibre reinforced composites and polymer blends 6 th International Conference on Modification Degradation and stabilization of Polymers, (MoDeSt2010), Athens, 5-9 Sep 2010. 27. N. Miskolczi, Cs. Varga, H. Szakács,. tgonzul, V. Sedlařík, S. Ganbold, T. Kitano, A. Gregorova: Compatibilization effect of polyalkenyl-polymaleicanhydride based derivates in polyamide-polyester sytems Konference Plastko 2010, Sborník, 13-14 April 2010. ISBN 978-80-7318-909-9, 309-310. 11