In this study, semiconductive poly (lactic acid) (PLA)/carbon nanotube (CNT) nanocomposites have been simultaneously subjected to melt-compounding and foaming using a continuous and single-step extrusion foaming process. The extrusion foaming process with the ability to be developed on an industrial scale is a complex process for a biopolymer in the presence of nanoparticles, chemical foaming agent, and chain extender, and to control it, knowledge about the phenomena occurring during the process and the structural properties of the foam is required. Although the extrusion foaming of PLA has been studied before, the simultaneous effects of chain extender content and nanoparticle loading on the microstructure and phenomena during the PLA extrusion foaming process have not been thoroughly investigated. The results of this study show that the two investigated variables have a strong interaction with each other. Increasing the chain extender content has led to a change in the rheological properties of the melt, as a result, it has been significantly effective in the nanoparticle dispersion state. Besides, the loading of nanoparticles has a powerful effect on the intensity of the chain extension reaction of PLA chains by the chain extender additive. The lightest extruded foams (with a void fraction of 0.52) with the highest cell density (5 × 106 cells/cm3), the smallest cell size (about 50 and 200 µm for number- and volume-average cell diameters), and the most uniform cell size distribution have been obtained in the middle values of the chain extender content (5 phr) and the lowest values of the nanoparticle loading (0.25 phr).
SunJZhaoZPangY, et al.The facile and efficient fabrication of rice husk/poly (lactic acid) foam composites by coordinated the interface combination and bubble hole structure. Int J Biol Macromol2023; 234: 123734.
2.
Yousefi KananiARennieAEWAbd RahimSZB. Additively manufactured foamed polylactic acid for lightweight structures. Rapid Prototyp J2023; 29(1): 50–66.
3.
GhanemiRMousaviSRQewamiS, et al.Extrusion foaming of multiphasic polyethylene/ethylene-vinyl acetate copolymer/carbon nanotube mixtures: tailoring foam properties by selective localization of nanoparticles. J Cell Plast2023; 59: 0021955X231177811.
DasPNayakPKMuthusamyS, et al.Foams for thermal insulation. Polymeric Foams: Applications of Polymeric Foams2023; 2: 145–165.
6.
ShojaeiSRostami-Tapeh-EsmaeilERodrigueD. Polymer foams waste management: a focus on mechanical and chemical recycling. Polymeric Foams: Applications of Polymeric Foams2023; 2: 289–318.
7.
GuoYHanXFuY, et al.Effect of polyethylene foam on dynamic cushioning energy absorption of paper corrugation tubes. J Mech Sci Technol2022; 36(4): 1857–1865.
8.
PinheiroLAChinelattoMACanevaroloSV. The role of chain scission and chain branching in high density polyethylene during thermo-mechanical degradation. Polym Degrad Stabil2004; 86(3): 445–453. DOI: 10.1016/J.POLYMDEGRADSTAB.2004.05.016.
9.
LiuGWenSWangY, et al.Exfoliation and distribution behavior of graphene nanoplatelets in polystyrene-based foams fabricated by supercritical CO2 assisted microcellular foaming. Chem Eng Sci2022; 249: 117331.
10.
BandyopadhyayABasakGC. Studies on photocatalytic degradation of polystyrene. Mater Sci Technol2007; 23(3): 307–314. DOI: 10.1179/174328407X158640.
11.
DuttaASankarpandiSGhoshAK. Evaluation of polypropylene/clay nanocomposite foamability based on their morphological and rheological aspects. J Cell Plast2018; 54(5): 829–850.
12.
Baumhardt-NetoRDe PaoliMA. Mechanical degradation of polypropylene: effect of UV irradiation. Polym Degrad Stabil1993; 40(1): 59–64. DOI: 10.1016/0141-3910(93)90191-K.
13.
MoriR. Replacing all petroleum-based chemical products with natural biomass-based chemical products: a tutorial review. RSC Sustain2023; 1(2): 179–212. DOI: 10.1039/D2SU00014H.
14.
Madhavan NampoothiriKNairNRJohnRP. An overview of the recent developments in polylactide (PLA) research. Bioresour Technol2010; 101(22): 8493–8501.
15.
LitauszkiKGereDCziganyT, et al.Environmentally friendly packaging foams: investigation of the compostability of poly (lactic acid)-based syntactic foams. Sustain. Mater. Technol2023; 35: e00527.
16.
LiPZhuXKongM, et al.Fully biodegradable polylactide foams with ultrahigh expansion ratio and heat resistance for green packaging. Int J Biol Macromol2021; 183: 222–234.
17.
PengKMubarakSDiaoX, et al.Progress in the preparation, properties, and applications of PLA and its composite microporous materials by supercritical CO2: a review from 2020 to 2022. Polymers2022; 14(20): 4320.
18.
JafariAMirzaeiHShafieiMA, et al.Conductive poly(ε‐caprolactone)/polylactic acid scaffolds for tissue engineering applications: synergy effect of zirconium nanoparticles and polypyrrole. Polym Adv Technol2022; 33(5): 1427–1441.
19.
TylerBGullottiDMangravitiA, et al.Polylactic acid (PLA) controlled delivery carriers for biomedical applications. Adv Drug Deliv Rev2016; 107: 163–175.
20.
OsmanMAVirgilioNRouabhiaM, et al.Polylactic acid (PLA) foaming: design of experiments for cell size control. Mater Sci Appl2022; 13(2): 63–77.
21.
EavesD. Handbook of polymer foams. Shrewsbury: iSmithers Rapra Publishing, 2004.
22.
WangGZhaoJWangG, et al.Strong and super thermally insulating in-situ nanofibrillar PLA/PET composite foam fabricated by high-pressure microcellular injection molding. Chem Eng J (Amsterdam, Neth)2020; 390: 124520.
23.
KmettyÁLitauszkiKRétiD. Characterization of different chemical blowing agents and their applicability to produce poly (lactic acid) foams by extrusion. Appl Sci2018; 8(10): 1960.
24.
BrüttingCDreierJBontenC, et al.Glass transition of PLA-CO2 mixtures after solid-state saturation. J Cell Plast2022; 58(6): 917–931. DOI: 10.1177/0021955X221144543/ASSET/IMAGES/LARGE/10.1177_0021955X221144543-FIG10.JPEG.
25.
MilovanovicSPajnikJLukicI. Tailoring of advanced poly (lactic acid)-based materials: a review. J Appl Polym Sci2022; 139(12): 51839.
26.
LiYYinDLiuW, et al.Fabrication of biodegradable poly (lactic acid)/carbon nanotube nanocomposite foams: significant improvement on rheological property and foamability. Int J Biol Macromol2020; 163: 1175–1186.
27.
NofarM. Effects of nano-/micro-sized additives and the corresponding induced crystallinity on the extrusion foaming behavior of PLA using supercritical CO2. Mater Des2016; 101: 24–34.
VenkatesanKBKarkhanisSSMatuanaLM. Microcellular foaming of poly (lactic acid) branched with food-grade chain extenders. J Appl Polym Sci2021; 138(29): 50686.
30.
ZongQXuAChaiK, et al.Increased expansion ratio, cell density, and compression strength of microcellular poly(lactic acid) foams via lignin graft poly(lactic acid) as a biobased nucleating agent. Polym Adv Technol2020; 31(10): 2239–2249. DOI: 10.1002/pat.4944.
31.
LiuWWuXOuY, et al.Electrically conductive and light-weight branched polylactic acid-based carbon nanotube foams. E-Polymers2021; 21(1): 96–107.
32.
ZhangRCaiCLiuQ, et al.Enhancing the melt strength of poly(lactic acid) via micro-crosslinking and blending with poly(butylene adipate-co-butylene Terephthalate)for the preparation of foams. J Polym Environ2017; 25(4): 1335–1341. DOI: 10.1007/s10924-016-0911-3.
33.
MihaiMHuneaultMAFavisBD. Rheology and extrusion foaming of chain-branched poly (lactic acid). Polym Eng Sci2010; 50(3): 629–642.
34.
KhademiSMHHemmatiFAroonMA. An insight into different phenomena involved in continuous extrusion foaming of biodegradable poly (lactic acid)/expanded graphite nanocomposites. Int J Biol Macromol2020; 157: 470–483.
35.
SoleimanpourAKhonakdarHMousaviSR, et al.Continuous extrusion foaming process of biodegradable nanocomposites based on poly (lactic acid)/carbonaceous nanoparticles with different geometric shapes: an insight into involved physical, chemical and rheological phenomena. J Appl Polym Sci2023; 140(19): e53822.
36.
CharoeythornkhajhornchaiPKhamloetWNungjumnongP. Effect of carbon allotropes on foam formation, cure characteristics, mechanical and thermal properties of NRF/carbon composites. J Cell Plast2022; 58(1): 41–57.
37.
LiuWZhuXGaoH, et al.Preparation and characterization of PLA foam chain extended through grafting octa (epoxycyclohexyl) POSS onto carbon nanotubes. Cell Polym2020; 39(3): 117–138.
38.
QewamiSMousaviSRGhanemiR, et al.An insight into simultaneous phase transition phenomena and melt-rheology of low-density polyethylene/ethylene–vinyl acetate copolymer/expanded graphite nanocomposites through continuous extrusion foaming process. Eur Polym J2023; 182: 111729.
39.
TiwaryPParkCBKontopoulouM. Transition from microcellular to nanocellular PLA foams by controlling viscosity, branching and crystallization. Eur Polym J2017; 91: 283–296.
40.
ShojaeiMJMéheustYOsmanA, et al.Combined effects of nanoparticles and surfactants upon foam stability. Chem Eng Sci2021; 238: 116601.
41.
NofarMSalehiyanRRaySS. Influence of nanoparticles and their selective localization on the structure and properties of polylactide-based blend nanocomposites. Composites Part B2021; 215: 108845.
42.
LudwiczakJKozlowskiM. Foaming of polylactide in the presence of chain extender. J Polym Environ2015; 23: 137–142.
43.
MorlinBLitauszkiKPetrényR, et al.Characterization of polylactic acid-based nanocomposite foams with supercritical CO2. Measurement2021; 178: 109385.
44.
LiSLiaoXXiaoW, et al.The improved foaming behavior of PLA caused by the enhanced rheology properties and crystallization behavior via synergistic effect of carbon nanotubes and graphene. J Appl Polym Sci2022; 139(13): 51874.
45.
DinhQVVoTQKimBH. Viscous heating and temperature profiles of liquid water flows in copper nanochannel. J Mech Sci Technol2019; 33(7): 3257–3263. DOI: 10.1007/S12206-019-0621-6/METRICS.
46.
WangXZhouHLiuB, et al.Chain extension and foaming behavior of poly (lactic acid) by functionalized multiwalled carbon nanotubes and chain extender. Adv Polym Technol2014; 33(S1): 21444.
47.
AugéM-ORoncucciDBourbigotS, et al.Recent advances on reactive extrusion of Poly (lactic acid). Eur Polym J2022; 184: 111727.
48.
SoleimanpourAKhonakdarHMousaviSR, et al.Dynamic crystallization kinetics and morphology of carbonaceous nanofillers-reinforced poly (lactic acid) foams. Thermochim Acta2022; 716: 179308.
49.
LiuTFengHZengW, et al.Facile fabrication of absorption-dominated biodegradable poly (lactic acid)/polycaprolactone/multi-walled carbon nanotube foams towards electromagnetic interference shielding. J Compos Sci2023; 7(9): 395.
50.
YangBWangDChenF, et al.Melting and crystallization behaviors of poly (lactic acid) modified with graphene acting as a nucleating agent. J Macromol Sci Part B2019; 58(2): 290–304.
51.
NajafiNHeuzeyM-CCarreauPJ, et al.Rheological and foaming behavior of linear and branched polylactides. Rheol Acta2014; 53: 779–790.
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
