Abstract
In this work, halloysite nanotubes (HNTs) and functionalized HNTs–APTES (aminopropyltriethoxysilane) in concentrations 0.5, 1 and 2.5 wt% were used as nanofillers in the synthesis of poly(ε-caprolactone) (PCL) nanocomposites via the in situ ring-opening polymerization of ε-caprolactone (CL). The successful functionalization of HNTs was confirmed with X-ray photoelectron spectroscopy. The effects of HNTs and HNTs–APTES on the polymerization procedure and on the thermal properties of PCL were studied in detail. It was found that both nanofillers reduced the \( \bar{M} \)n values of the resulting nanocomposites, with the unfunctionalized one reducing it in a higher extent, while SEM micrographs indicated satisfactory dispersion in the PCL matrix. The crystallization study under isothermal and dynamic conditions revealed the nucleating effect of the nanotubes. The functionalization of nanotubes enabled even faster rates and attributed higher nucleation activity as a result of better dispersion and the formation of a strong interface between the filler and the matrix. An in-depth kinetic analysis was performed based on the data from crystallization procedures. PLOM images confirmed the effectiveness of both fillers as heterogeneous nucleation agents. Finally, from TGA analysis, it was found that HNTs did not affect the thermal stability of PCL while for HNTs–APTES, a small decrease in Tmax was observed, of about 5 °C for all filler contents.
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Liu M, Jia Z, Jia D, Zhou C (2014) Recent advance in research on halloysite nanotubes-polymer nanocomposite. Prog Polym Sci 39:1498–1525. https://doi.org/10.1016/j.progpolymsci.2014.04.004
Bhattacharya M (2016) Polymer nanocomposites-A comparison between carbon nanotubes, graphene, and clay as nanofillers. Materials (Basel) 9:1–35. https://doi.org/10.3390/ma9040262
Bikiaris D (2011) Can nanoparticles really enhance thermal stability of polymers? Part II: an overview on thermal decomposition of polycondensation polymers. Thermochim Acta 523:25–45. https://doi.org/10.1016/j.tca.2011.06.012
Chrissafis K, Bikiaris D (2011) Can nanoparticles really enhance thermal stability of polymers? Part I: an overview on thermal decomposition of addition polymers. Thermochim Acta 523:1–24. https://doi.org/10.1016/j.tca.2011.06.010
Papageorgiou GZ, Achilias DS, Bikiaris DN, Karayannidis GP (2005) Crystallization kinetics and nucleation activity of filler in polypropylene/surface-treated SiO2 nanocomposites. Thermochim Acta 427:117–128. https://doi.org/10.1016/j.tca.2004.09.001
Papageorgiou GZ, Karandrea E, Giliopoulos D et al (2014) Effect of clay structure and type of organomodifier on the thermal properties of poly(ethylene terephthalate) based nanocomposites. Thermochim Acta 576:84–96. https://doi.org/10.1016/j.tca.2013.12.006
Papageorgiou GZ, Terzopoulou Z, Achilias DS et al (2013) Biodegradable poly(ethylene succinate) nanocomposites. Effect of filler type on thermal behaviour and crystallization kinetics. Polymer (United Kingdom) 54:4604–4616. https://doi.org/10.1016/j.polymer.2013.06.005
Papageorgiou GZ, Terzopoulou Z, Bikiaris D et al (2014) Evaluation of the formed interface in biodegradable poly(l-lactic acid)/graphene oxide nanocomposites and the effect of nanofillers on mechanical and thermal properties. Thermochim Acta 597:48–57. https://doi.org/10.1016/j.tca.2014.10.007
Terzopoulou Z, Patsiaoura D, Papageorgiou DG et al (2017) Effect of MWCNTs and their modification on crystallization and thermal degradation of poly(butylene naphthalate). Thermochim Acta 656:59–69. https://doi.org/10.1016/j.tca.2017.08.012
Sengupta R, Bhattacharya M, Bandyopadhyay S, Bhowmick AK (2011) A review on the mechanical and electrical properties of graphite and modified graphite reinforced polymer composites. Prog Polym Sci 36:638–670
Leslie-Pelecky DL, Rieke RD (1996) Magnetic properties of nanostructured materials. Chem Mater 8:1770–1783. https://doi.org/10.1021/cm960077f
Sanchez C, Lebeau B, Chaput F, Boilot J-P (2003) Optical properties of functional hybrid organic-inorganic nanocomposites. Adv Mater 15:1969–1994. https://doi.org/10.1002/adma.200300389
Armentano I, Dottori M, Fortunati E et al (2010) Biodegradable polymer matrix nanocomposites for tissue engineering: a review. Polym Degrad Stab 95:2126–2146. https://doi.org/10.1016/j.polymdegradstab.2010.06.007
Kloprogge JT (1998) Synthesis of smectites and porous pillared clay catalysts: a review. J Porous Mater 5:5–41. https://doi.org/10.1023/A:1009625913781
Murray HH (1991) Overview—clay mineral applications. Appl Clay Sci 5:379–395. https://doi.org/10.1016/0169-1317(91)90014-Z
Joussein E, Petit S, Churchman J et al (2005) Halloysite clay minerals—a review. Clay Miner 40:383–426. https://doi.org/10.1180/0009855054040180
Lvov YM, DeVilliers MM, Fakhrullin RF (2016) The application of halloysite tubule nanoclay in drug delivery. Expert Opin Drug Deliv 5247:1–10. https://doi.org/10.1517/17425247.2016.1169271
Du M, Guo B, Jia D (2010) Newly emerging applications of halloysite nanotubes: a review. Polym Int 59:574–582. https://doi.org/10.1002/pi.2754
Peixoto AF, Fernandes AC, Pereira C et al (2016) Physicochemical characterization of organosilylated halloysite clay nanotubes. Microporous Mesoporous Mater 219:145–154. https://doi.org/10.1016/j.micromeso.2015.08.002
Labet M, Thielemans W (2009) Synthesis of polycaprolactone: a review. Chem Soc Rev 38:3484. https://doi.org/10.1039/b820162p
Mondal D, Griffith M, Venkatraman SS (2016) Polycaprolactone-based biomaterials for tissue engineering and drug delivery: current scenario and challenges. Int J Polym Mater Polym Biomater 65:255–265. https://doi.org/10.1080/00914037.2015.1103241
Marco Zanetti, Sergei L, Giovanni Camino (2000) Polymer layered silicate nanocomposites. Macromol Mater Eng 279:1–9. https://doi.org/10.1002/1439-2054(20000601)279:1%3C1::AID-MAME1%3E3.0.CO;2-Q/full
Kuo SW, Huang WJ, Huang SB et al (2003) Syntheses and characterizations of in situ blended metallocence polyethylene/clay nanocomposites. Polymer (Guildf) 44:7709–7719. https://doi.org/10.1016/j.polymer.2003.10.007
Kim J, Kwak S, Hong SM et al (2010) Nonisothermal crystallization behaviors of nanocomposites prepared by in situ polymerization of high-density polyethylene on multiwalled carbon nanotubes. Macromolecules 43:10545–10553. https://doi.org/10.1021/ma102036h
Zou H, Wu S, Shen J (2008) Polymer/silica nanocomposites: preparation, characterization, properties, and applications. Chem Rev 108:3893–3957. https://doi.org/10.1021/cr068035q
Vikas M (ed) (2011) In-situ synthesis of polymer nanocomposites. In: In-situ synthesis of polymer nanocomposites. Wiley, Weinheim, pp 1–25
Lahcini M, Elhakioui S, Szopinski D et al (2016) Harnessing synergies in tin-clay catalyst for the preparation of poly(ϵ-caprolactone)/halloysite nanocomposites. Eur Polym J 81:1–11. https://doi.org/10.1016/j.eurpolymj.2016.05.014
Bhagabati P, Chaki TK, Khastgir D (2015) One-step in situ modification of halloysite nanotubes: augmentation in polymer-filler interface adhesion in nanocomposites. Ind Eng Chem Res 54:6698–6712. https://doi.org/10.1021/acs.iecr.5b01043
Vieira Marques MDF, da Silva Rosa JL, da Silva MCV (2017) Nanocomposites of polypropylene with halloysite nanotubes employing in situ polymerization. Polym Bull 74:2447–2464. https://doi.org/10.1007/s00289-016-1848-3
Zhao M, Liu P (2008) Halloysite nanotubes/polystyrene (HNTs/PS) nanocomposites via in situ bulk polymerization. J Therm Anal Calorim 94:103–107. https://doi.org/10.1007/s10973-007-8677-4
Lin Y, Ng KM, Chan C-M et al (2011) High-impact polystyrene/halloysite nanocomposites prepared by emulsion polymerization using sodium dodecyl sulfate as surfactant. J Colloid Interface Sci 358:423–429. https://doi.org/10.1016/j.jcis.2011.03.009
Barkoula NM, Alcock B, Cabrera NO, Peijs T (2008) Fatigue properties of highly oriented polypropylene tapes and all-polypropylene composites. Polym Polym Compos 16:101–113
Marini J, Pollet E, Averous L, Bretas RES (2014) Elaboration and properties of novel biobased nanocomposites with halloysite nanotubes and thermoplastic polyurethane from dimerized fatty acids. Polymer (Guildf) 55:5226–5234. https://doi.org/10.1016/j.polymer.2014.08.049
Gong B, Ouyang C, Gao Q et al (2016) Synthesis and properties of a millable polyurethane nanocomposite based on castor oil and halloysite nanotubes. RSC Adv 6:12084–12092. https://doi.org/10.1039/C5RA21586B
Haroosh HJ, Dong Y, Chaudhary DS et al (2013) Electrospun PLA: pCL composites embedded with unmodified and 3-aminopropyltriethoxysilane (ASP) modified halloysite nanotubes (HNT). Appl Phys A Mater Sci Process 110:433–442. https://doi.org/10.1007/s00339-012-7233-7
Du M, Guo B, Liu M, Jia D (2006) Preparation and characterization of polypropylene grafted halloysite and their compatibility effect to polypropylene/halloysite composite. Polym J 38:1198–1204. https://doi.org/10.1295/polymj.PJ2006038
Albdiry MT, Yousif BF (2013) Morphological structures and tribological performance of unsaturated polyester based untreated/silane-treated halloysite nanotubes. Mater Des 48:68–76. https://doi.org/10.1016/j.matdes.2012.08.035
Chen S, Lu X, Wang T, Zhang Z (2015) Preparation and characterization of mechanically and thermally enhanced polyimide/reactive halloysite nanotubes nanocomposites. J Polym Res. https://doi.org/10.1007/s10965-015-0806-3
Roumeli E, Papageorgiou DG, Tsanaktsis V et al (2015) Amino-functionalized multiwalled carbon nanotubes lead to successful ring-opening polymerization of poLY(ε-caprolactone): enhanced interfacial bonding and optimized mechanical properties. ACS Appl Mater Interfaces 7:11683–11694. https://doi.org/10.1021/acsami.5b03693
Shi Y-F, Tian Z, Zhang Y et al (2011) Functionalized halloysite nanotube-based carrier for intracellular delivery of antisense oligonucleotides. Nanoscale Res Lett 6:608. https://doi.org/10.1186/1556-276X-6-608
Roumeli E, Avgeropoulos A, Pavlidou E et al (2014) Understanding the mechanical and thermal property reinforcement of crosslinked polyethylene by nanodiamonds and carbon nanotubes. RSC Adv 4:45522–45534. https://doi.org/10.1039/c4ra05585c
Roumeli E, Pavlidou E, Avgeropoulos A et al (2014) Factors controlling the enhanced mechanical and thermal properties of nanodiamond-reinforced cross-linked high density polyethylene. J Phys Chem B. https://doi.org/10.1021/jp504531f
Vassiliou AA, Papageorgiou GZ, Achilias DS, Bikiaris DN (2007) Non-isothermal crystallisation kinetics of in situ prepared poly(ε-caprolactone)/surface-treated SiO2 nanocomposites. Macromol Chem Phys 208:364–376. https://doi.org/10.1002/macp.200600447
Michell RM, Mugica A, Zubitur M, Müller AJ (2017) Self-nucleation of crystalline phases within homopolymers, polymer blends, copolymers, and nanocomposites. In: Auriemma F, Alfonso GC, de Rosa C (eds) Polymer crystallization I: from chain microstructure to processing. Springer, Cham, pp 215–256
Arnal ML, Balsamo V, Ronca G et al (2000) Applications of successive self-nucleation and annealing (SSA) to polymer characterization. J Therm Anal Calorim 59:451–470. https://doi.org/10.1023/A:1010137408023
Muller AJ, Albuerne J, Marquez L et al (2005) Self-nucleation and crystallization kinetics of double crystalline poly(p-dioxanone)-b-poly(ε-caprolactone) diblock copolymers. Faraday Discuss 128:231–252. https://doi.org/10.1039/B403085K
Yuan P, Southon PD, Liu Z et al (2008) Functionalization of halloysite clay nanotubes by grafting with γ-aminopropyltriethoxysilane. J Phys Chem C 112:15742–15751. https://doi.org/10.1021/jp805657t
Ng KM, Lau YTR, Chan CM et al (2011) Surface studies of halloysite nanotubes by XPS and ToF-SIMS. Surf Interface Anal 43:795–802. https://doi.org/10.1002/sia.3627
Hillier S, Brydson RIK, Delbos E et al (2016) Correlations among the mineralogical and physical properties of halloysite nanotubes (HNTs). Clay Miner 51:1–59
Hu P, Yang H (2013) Insight into the physicochemical aspects of kaolins with different morphologies. Appl Clay Sci 74:58–65. https://doi.org/10.1016/j.clay.2012.10.003
Luo P, Zhang J, Zhang B et al (2011) Preparation and characterization of silane coupling agent modified halloysite for Cr(VI) removal. Ind Eng Chem Res 50:10246–10252
Kricheldorf HR, Berl M, Scharnagl N (1988) Poly(lactones). 9. Polymerization Mechanism of metal alkoxide initiated polymerizations of lactide and various lactones. Macromolecules 21:286–293
Papageorgiou DG, Kinloch IA, Young RJ (2017) Mechanical properties of graphene and graphene-based nanocomposites. Prog Mater Sci 90:75–127
Navarro-Baena I, Marcos-Fernandez A, Kenny JM, Peponi L (2014) Crystallization behavior of diblock copolymers based on PCL and PLLA biopolymers. J Appl Crystallogr 47:1948–1957. https://doi.org/10.1107/S1600576714022468
Abdelrazek EM, Hezma AM, El-khodary A, Elzayat AM (2016) Spectroscopic studies and thermal properties of PCL/PMMA biopolymer blend. Egypt J Basic Appl Sci 3:10–15. https://doi.org/10.1016/j.ejbas.2015.06.001
Gloria A, Russo T, D’Amora U et al (2013) Magnetic poly(ε-caprolactone)/iron-doped hydroxyapatite nanocomposite substrates for advanced bone tissue engineering. J R Soc Interface 10:20120833. https://doi.org/10.1098/rsif.2012.0833
Rezaei A, Mohammadi MR (2013) In vitro study of hydroxyapatite/polycaprolactone (HA/PCL) nanocomposite synthesized by an in situ sol–gel process. Mater Sci Eng C 33:390–396. https://doi.org/10.1016/j.msec.2012.09.004
Fabbri P, Bondioli F, Messori M et al (2010) Porous scaffolds of polycaprolactone reinforced with in situ generated hydroxyapatite for bone tissue engineering. J Mater Sci Mater Med 21:343–351. https://doi.org/10.1007/s10856-009-3839-5
Rooj S, Das A, Thakur V et al (2010) Preparation and properties of natural nanocomposites based on natural rubber and naturally occurring halloysite nanotubes. Mater Des 31:2151–2156. https://doi.org/10.1016/j.matdes.2009.11.009
Tham WL, Poh BT, Mohd Ishak ZA, Chow WS (2014) Thermal behaviors and mechanical properties of halloysite nanotube-reinforced poly(lactic acid) nanocomposites. J Therm Anal Calorim 118:1639–1647. https://doi.org/10.1007/s10973-014-4062-2
Lee K-S, Chang Y-W (2013) Thermal, mechanical, and rheological properties of poly(ε-caprolactone)/halloysite nanotube nanocomposites. J Appl Polym Sci 128:2807–2816. https://doi.org/10.1002/app.38457
Di Lorenzo ML, Silvestre C (1999) Non-isothermal crystallization of polymers. Prog Polym Sci 24:917–950. https://doi.org/10.1016/S0079-6700(99)00019-2
Nerantzaki M, Papageorgiou GZ, Bikiaris DN (2014) Effect of nanofiller’s type on the thermal properties and enzymatic degradation of poly(ε-caprolactone). Polym Degrad Stab 108:257–268. https://doi.org/10.1016/j.polymdegradstab.2014.03.018
Guan W, Qiu Z (2012) Isothermal crystallization kinetics, morphology, and dynamic mechanical properties of biodegradable poly(ε-caprolactone) and octavinyl-polyhedral oligomeric silsesquioxanes nanocomposites. Ind Eng Chem Res 51:3203–3208. https://doi.org/10.1021/ie202802d
Pan H, Yu J, Qiu Z (2011) Crystallization and morphology studies of biodegradable poly(ϵ-caprolactone)/polyhedral oligomeric silsesquioxanes nanocomposites. Polym Eng Sci 51:2159–2165. https://doi.org/10.1002/pen.21983
Qiu Z, Wang H, Xu C (2011) Crystallization, mechanical properties, and controlled enzymatic degradation of biodegradable poly(ε-caprolactone)/multi-walled carbon nanotubes nanocomposites. J Nanosci Nanotechnol 11:7884–7893. https://doi.org/10.1166/jnn.2011.4714
Avrami M (1941) Granulation, phase change, and microstructure kinetics of phase change III. J Chem Phys 9:177–184. https://doi.org/10.1063/1.1750872
Avrami M (1940) Kinetics of phase change. II transformation-time relations for random distribution of nuclei. J Chem Phys 8:212–224. https://doi.org/10.1063/1.1750631
Avrami M (1939) Kinetics of phase change. I general theory. J Chem Phys 7:1103–1112. https://doi.org/10.1063/1.1750380
Lorenzo AT, Arnal ML, Albuerne J, Müller AJ (2007) DSC isothermal polymer crystallization kinetics measurements and the use of the Avrami equation to fit the data: guidelines to avoid common problems. Polym Test 26:222–231. https://doi.org/10.1016/j.polymertesting.2006.10.005
Hoffman JD, Miller RL (1997) Kinetic of crystallization from the melt and chain folding in polyethylene fractions revisited: theory and experiment. Polymer (Guildf) 38:3151–3212. https://doi.org/10.1016/S0032-3861(97)00071-2
Papageorgiou DG, Papageorgiou GZ, Bikiaris DN, Chrissafis K (2013) Crystallization and melting of propylene–ethylene random copolymers. Homogeneous nucleation and β-nucleating agents. Eur Polym J 49:1577–1590. https://doi.org/10.1016/j.eurpolymj.2013.02.002
Nanaki SG, Papageorgiou GZ, Bikiaris DN (2012) Crystallization of novel poly(ε-caprolactone)-block-poly(propylene adipate) copolymers. J Therm Anal Calorim 108:633–645. https://doi.org/10.1007/s10973-011-2155-8
Lopez JV, Perez-Camargo RA, Zhang B et al (2016) The influence of small amounts of linear polycaprolactone chains on the crystallization of cyclic analogue molecules. RSC Adv 6:48049–48063. https://doi.org/10.1039/C6RA04823D
Di Maio E, Iannace S, Sorrentino L, Nicolais L (2004) Isothermal crystallization in PCL/clay nanocomposites investigated with thermal and rheometric methods. Polymer (Guildf) 45:8893–8900. https://doi.org/10.1016/j.polymer.2004.10.037
Siqueira G, Fraschini C, Bras J et al (2011) Impact of the nature and shape of cellulosic nanoparticles on the isothermal crystallization kinetics of poly(ε-caprolactone). Eur Polym J 47:2216–2227. https://doi.org/10.1016/j.eurpolymj.2011.09.014
Zhuravlev E, Schmelzer JWP, Wunderlich B, Schick C (2011) Kinetics of nucleation and crystallization in poly(ɛ-caprolactone) (PCL). Polymer (Guildf) 52:1983–1997. https://doi.org/10.1016/j.polymer.2011.03.013
Di Y, Iannace S, Di Maio E, Nicolais L (2003) Nanocomposites by melt intercalation based on polycaprolactone and organoclay. J Polym Sci Part B Polym Phys 41:670–678. https://doi.org/10.1002/polb.10420
Dobreva A, Gutzow I (1993) Activity of substrates in the catalyzed nucleation of glass-forming melts. I. Theory. J Non Cryst Solids 162:1–12. https://doi.org/10.1016/0022-3093(93)90736-H
Dobreva A, Gutzow I (1993) Activity of substrates in the catalyzed nucleation of glass-forming melts. II. Experimental evidence. J Non Cryst Solids 162:13–25. https://doi.org/10.1016/0022-3093(93)90737-I
Vyazovkin S, Dranca I (2006) Isoconversional analysis of combined melt and glass crystallization data. Macromol Chem Phys 207:20–25. https://doi.org/10.1002/macp.200500419
Vyazovkin S, Burnham AK, Criado JM et al (2011) ICTAC kinetics committee recommendations for performing kinetic computations on thermal analysis data. Thermochim Acta 520:1–19. https://doi.org/10.1016/j.tca.2011.03.034
Friedman HL (1964) Kinetics of thermal degradation of char-forming plastics from thermogravimetry. Application to a phenolic plastic. J Polym Sci Part C Polym Symp 6:183–195. https://doi.org/10.1002/polc.5070060121
Vyazovkin S, Sbirrazzuoli N (2002) Isoconversional analysis of the nonisothermal crystallization of a polymer melt. Macromol Rapid Commun 23:766–770. https://doi.org/10.1002/1521-3927(20020901)23:13<766::AID-MARC766>3.0.CO;2-0/abstract
Bosq N, Guigo N, Zhuravlev E, Sbirrazzuoli N (2013) Nonisothermal crystallization of polytetrafluoroethylene in a wide range of cooling rates. J Phys Chem B 117:3407–3415. https://doi.org/10.1021/jp311196g
Vyazovkin S, Sbirrazzuoli N (2003) Estimating the activation energy for non-isothermal crystallization of polymer melts. J Therm Anal Calorim 72:681–686. https://doi.org/10.1023/A:1024506522878
Papageorgiou DG, Chrissafis K, Pavlidou E et al (2014) Effect of nanofiller’s size and shape on the solid state microstructure and thermal properties of poly(butylene succinate) nanocomposites. Thermochim Acta 590:181–190. https://doi.org/10.1016/j.tca.2014.06.030
Vyazovkin S, Sbirrazzuoli N (2004) Isoconversional approach to evaluating the Hoffman–Lauritzen parameters (U* and Kg) from the overall rates of nonisothermal crystallization. Macromol Rapid Commun 25:733–738. https://doi.org/10.1002/marc.200300295
Dong Y, Marshall J, Haroosh HJ et al (2015) Polylactic acid (PLA)/halloysite nanotube (HNT) composite mats: influence of HNT content and modification. Compos Part A Appl Sci Manuf 76:28–36. https://doi.org/10.1016/j.compositesa.2015.05.011
Cervantes-Uc JM, Cauich-Rodríguez JV, Vázquez-Torres H et al (2007) Thermal degradation of commercially available organoclays studied by TGA–FTIR. Thermochim Acta 457:92–102. https://doi.org/10.1016/j.tca.2007.03.008
Papageorgiou DG, Roumeli E, Terzopoulou Z et al (2015) Polycaprolactone/multi-wall carbon nanotube nanocomposites prepared by in situ ring opening polymerization: decomposition profiling using thermogravimetric analysis and analytical pyrolysis-gas chromatography/mass spectrometry. J Anal Appl Pyrolysis. https://doi.org/10.1016/j.jaap.2015.07.007
Nitya G, Nair GT, Mony U et al (2012) In vitro evaluation of electrospun PCL/nanoclay composite scaffold for bone tissue engineering. J Mater Sci Mater Med 23:1749–1761. https://doi.org/10.1007/s10856-012-4647-x
Torres E, Fombuena V, Vallés-Lluch A, Ellingham T (2017) Improvement of mechanical and biological properties of polycaprolactone loaded with hydroxyapatite and halloysite nanotubes. Mater Sci Eng C 75:418–424. https://doi.org/10.1016/j.msec.2017.02.087
Jing X, Mi HY, Turng LS (2017) Comparison between PCL/hydroxyapatite (HA) and PCL/halloysite nanotube (HNT) composite scaffolds prepared by co-extrusion and gas foaming. Mater Sci Eng C 72:53–61. https://doi.org/10.1016/j.msec.2016.11.049
Acknowledgements
The authors would like to thank Associate Professor Konstantinos Triantafyllidis of the Laboratory of Chemical and Environmental Technology, Department of Chemistry, Aristotle University of Thessaloniki, for the nitrogen adsorption/desorption experiments.
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Terzopoulou, Z., Papageorgiou, D.G., Papageorgiou, G.Z. et al. Effect of surface functionalization of halloysite nanotubes on synthesis and thermal properties of poly(ε-caprolactone). J Mater Sci 53, 6519–6541 (2018). https://doi.org/10.1007/s10853-018-1993-1
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DOI: https://doi.org/10.1007/s10853-018-1993-1