plasticized bionanocomposites in films in contact …
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PLASTICIZED BIONANOCOMPOSITES IN FILMS IN CONTACT WITH SKIN
M.-B. Coltelli, V. Gigante, A. Vannozzi, L. Aliotta, S. Danti, L. Panariello, A. Lazzeri
Conference ICAMP2018
University of Pisa, Department of Civil and Industrial Engineering (DICI-UNIPI)
InterUniversity Consortium of Materials Science and Technology (INSTM)
Replacing petro-based materials with renewable biodegradable counterparts is a correct strategy fortaking care of the environment, considering both sources and end of life related best practices inview of boosting the application of circular economy principles. Bioplastics play a fundamental role
On 2017 the composting was considered by EU a method of waste management identical to recycling and was defined “organic recycling”
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Personal care sector, considering monouse products in contact with body, has the possibility of much exploiting these materials
Thanks to POLYBIOSKIN project
Poly(lactic acid) (PLA)
Renewable
Compostable
Trasparent
Good processability
Advantages
PLA, yet produced on a large scale and having a cost similar to commodities, is a good
candidate for producing biodegradable films products
Excessive rigidity
Brittleness
Low crystal. rate
Disadvantages
Mature technology (about 210000 ton/year)
Cost: about 15 % more than PET
The possibility of using it in films in contact with skin in the diaper and fem pads sector, isstrongly linked to its high compatibility with body and reported slight biocidal effect (book: NPSChauhan, Biocidal polymers, 2016). Moreover it is necessary also processing it by flat dieextrusion to obtain flexible films
FLAT DIE EXTRUSION PROCESSEXTRUSION
screws
granules
Important parameters to control melt viscosity during processing :
the torque of extruder screws and the Melt Flow Rate (MFR) of
the obtained material
EXTRUDER at UNIPI FLAT DIE ACCESSORY
The possibility of using it in films in contact with skin in the diaper and fem pads sector, isstrongly linked to its high compatibility with body and reported slight biocidal effect (book:Biocidal polymers, 2016) and the possibility of processing it by flat die extrusion to obtainflexible films
Mechanical TestsThermal Analysis
Spectroscopy
Morphology
Additives Properties ApplicationsProcessing
technologiesReferences
Polymers
Increased
impact
properties,
increased strain
at break
Rigid
packaging
Flat die extrusion
(followed by
thermoforming),
injection moulding
-F. Signori, M. B. Coltelli, S. Bronco, F. Ciardelli, Polym. Degr. Stab., 2009, 94, 74–82
-MB Coltelli, C. Toncelli, F. Ciardelli, S. Bronco, Polym. Degr. Stab., 2011, 96, 982-990
-S. Farsetti, B. Cioni and A. Lazzeri, Macromol. Symp. 301, 82–89 (2011)
-V. T. Phuong, M. B. Coltelli, P. Cinelli, M. Cifelli, S. Verstichel and A. Lazzeri, Polymer 55, 4498-
4513(2014)
-V.Gigante, I.Canesi, P. Cinelli, M.B. Coltelli, A. Lazzeri, Eur. Poly. Jour., 115,125 (2019)
-M.-B. Coltelli, N. Mallegni, S Rizzo, Cinelli, Lazzeri, Materials, 2019
Plasticizers
Decreased
Modulus and
increased strain
at break
Flexible
packagingFlat die extrusion,
blow extrusion
-M-B. Coltelli, I. Della Maggiore, M. Bertoldo, S. Bronco, F. Signori, F. Ciardelli, Journal of Applied
Polymer Science, 110 (2), 1250-1262 (2008)
-M. K. Fehri, P. Cinelli, M. B. Coltelli, I. Anguillesi and A. Lazzeri, Int. Jour. Chem. Engin. Appl., 7(2), 85-
88 (2016)
-N. Mallegni, V. T. Phuong, M. B. Coltelli, M. B. Coltelli, P. Cinelli, A. Lazzeri, Materials 11(1):148, 2018
Melt strength
enhancers
Increased melt
strength
Flexible
packagingFlat die extrusion,
blow extrusion-M.-B. Coltelli, S. Bronco, C. Chinea, Polym. Degr. Stab., 2010, 95, 332-341
-A. Lazzeri, V. T. Phuong and P. Cinelli, WO2013164743 A1 (7 nov 2013)
FillersIncreased
Elastic Modulus
and tensile
strength
Rigid
packaging
Flat die extrusion
(followed by
thermoforming),
injection moulding
-A. Lazzeri and V.T. Phuong, Compos. Sci. Technol., 93, 106–113 (2014)
-V. Gigante, L. Aliotta, V.T. Phuong, M. B. Coltelli, P. Cinelli, A. Lazzeri, Composites Science and
Technology 152, 2017, DOI10.1016/j.compscitech.2017.09.008
-L. Aliotta, P. Cinelli, M. B. Coltelli, A. Lazzeri, Eur. Pol. Jour, 113,78 (2019)
Nucleating
agents
Increased
crystallinity and
elastic Modulus
Rigid
packaging Injection moulding
-X. Shi, G. Zhang, T. V. Phuong and A. Lazzeri, Molecules, 20, 1579–1593 (2015)
-M. K. Fehri, C. Mugoni, P. Cinelli, I. Anguillesi, M. B. Coltelli, S. Fiori, M. Montorsi and A. Lazzeri, Expr.
Polym. Lett. 10 (4), 274–288 (2016)
-L. Aliotta, P. Cinelli, M.B. Coltelli, M.C. Righetti, M. Gazzano, A. Lazzeri, European Polymer Journal,
DOI 10.1016/j.eurpolymj.2017.04.041, 2017
Modulation of PLA properties
The plasticization of selected polymeric blends, obtained by using biodegradable and partially biobased polyesters aswell as a citrate, is the strategy followed to obtain materials with the suitable mechanical properties and amaximized renewable content.
Not plasticized plasticized
Coltelli et al., 2008
ATBC
PBAT = poly(butylene adipate-co-terephathalate)
ATBC is more
concentrated in
the PBAT
dispersed phase
IMPORTANCE OF PLASTICIZATION FOR FULL RENEWABILITY OF BIOPOLYESTERS BASED
BIOPLASTICS
• PLA is renewable
• ATBC is renewable
• Other biodegradable polyesters (PBAT, poly(butylene succinate) –PBS-) are not fully
renewable, because currently some reagents, potentially obtainable by biorefinery
(biomass), are not yet produced on a large scale.
To obtain products with a high content of biobased raw materials, exploitable as
such in a short term perspective, it is necessary to maximize the PLA content in
the materials. As the PLA is a very rigid material, the plasticization, making it
more ductile, is necessary.
POLYBIOSKIN threshold : at least 90% renewable
The plasticization of selected polymeric blends, obtained by using biodegradable and partially biobased polyesters aswell as ATBC, is the strategy followed to obtain materials with the suitable mechanical properties and a maximizedrenewable content (> 90%)→ P1: based on PLA/PBAT;→ P2: based on PLA/PBS
P1 MD P1 CD P2 MD P2 CD
E (GPa) ≈ 0.140 ≈0.111 ≈0.080 ≈0.080
σb (MPa) 21 ± 3 16 ± 1 20 ± 6 25.1 ± 5.5
εb (%) 380 ± 30 330 ± 20 410 ± 30 423.2 ± 46.1
The use of a melt strengthening agent wasfundamental to counterbalance the decrease inmelt viscosity, mainly due to addition of the liquidplasticizer
Preparation of flexible films by flat die extrusion
BlendTorque
(Ncm)
MFR
(g/10min)
PLA + PBS + ATBC 67,8 ± 5,4 23,6 ± 2,1
PLA + PBS + ATBC + PS 72,8 ± 6,0 12,4 ± 0,9
The compatibility of the films with keratynocytes and mesenchimal stromal cells
was found very good, with a slight anti-microbial action due to the activation of
defensins
P2
Oiliness of the surface after 10 days of storage
By controlling the weight of films kept in oven at 60°C it was found that ATBC migrated significantly from thefilms making them oily on the surface
Infrared-ATR characterization
P1
P2
P1 cooled roll
0
0,5
1
1,5
2
2,5
3
3,5
0 200 400 600 800 1000 1200 1400 1600
% o
f m
as
ss
loss
Time (h)
P2
F4e
Flat die extruded films
• The tensile properties,
measured immediately after the
extrusion and after one month,
were not significantly modified
• The oiliness developed at room
temperature disappeared
comparing F4e with P2
Structure of arthropodes
exoscheletonInter-macromolecolar hydrogen bonding
Each chitin nano-crystallite is composed of about 20 linear chains of poly(N-acetyl glucosamine)
the chitin resulting rigid
substance is immersed in a
matrix of proteins and calcium
carbonate
structure
nano-assembly
Interestingly, the microfibers form layers producing a plywood-like structure
On each layer a different orientation of the microfibers is achieved, thus making the material highly resistant.
The microfibers contain crystalline nano-fibers. It is possible
to produce chitin nano-whiskers by chemical treatment of
microfibers. MAVI SUD plant, Aprilia, (Italy) patented this
process. Nano-chitin is thus available in diluted water
suspension for cosmetic applications.
Dispersing chitin nanofibrils in PLA
0 1 2 3 4 5 6 7
0,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
1,6
1,8
micro-carbonate
nano-carbonate
% w
eig
ht lo
ss
% by weight of additive
Bionanocomposites: Preparation of plasticized PLA/PBS films containing chitin nanofibrils
Composition Torque (Ncm) MFR (g/10min)
PLA + PBS + ATBC 67,8 ± 5,4 23,6 ± 2,1
PLA + PBS + ATBC +PS 72,8 ± 6,0 12,4 ± 0,9
PLA + PBS + ATBC +NC 60,0 ± 4,1 18,4 ± 1,3
PLA + PBS + ATBC +NC +PS 63,3 ± 3,6 13,1 ± 1,3
Chitin nanofibrils could be potentially used to decrease
ATBC mass loss
Preparation of a nano-structured pre-composite
t= 60 days
Kinetic of plasticizer loss at 60°C
0
0,5
1
1,5
2
2,5
3
0 200 400 600 800 1000 1200 1400 1600 1800
% w
eig
ht
los
s
time (h)
F1
F2
F3
F4
F8
F14
Micro-calcium carbonate 7%
Chitin nanofibrils
Plastistrength
The lowest % of lost
mass with respect to the
weight of the film is
achieved by using micro-
calcium carbonate.
The kinetic of migration
can be better studied by
considering proper
models
Conclusions
Replacing petro-based plastics with biobased and biodegradable plastics like PLA would be positive to
develop evironmentally friendly products
For obtaining flexible films with suitable properties and compatible with skin the plasticization of PLA
with biobased liquid citrates and the blending with biodegradable polyesters is necessary to reach a
high content of renewable sources in the material
Moreover, the addition of calcium carbonate and other bionanofillers like chitin nanofibrils was
fundamental to modulate surficial properties of films. Interestingly the tendency of films to slowly partially
release plasticizer, negatively affecting surficial stickiness of films, can be prevented using inorganic
fillers.
The weight of released plasticizer by using micro-calcium carbonate is strongly limited. On the other
hand CN were demonstrated to act much onto kinetic of release, making it slower. These interesting
findings can be exploited for peculiar applications.
Acknowledgements
POLYBIOSKIN European project (GA N° 745839) is kindly acknowledged
Multifunctional Bio-
Ecocompatible Materials
lab (MBEM)
Pisa, Luminaria 2015
Thank you for your
attention