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Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
Istituto di Scienze e Tecnologie Molecolari
ISTM-CNR, Università degli Studi di Padova
e-mail: [email protected]
Silvia Gross
La chimica moderna e la sua comunicazione
Dipartimento di Scienze Chimiche
Università degli Studi di Padova
e-mail: [email protected]
http://www.chimica.unipd.it/silvia.gross/
Silvia Gross, Mara Natile
Chimica Inorganica III
Lezioni propedeutiche al laboratorio
a.a. 2018-2019
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
Experiments
0.Procedure speciali nell’attività di laboratorio (tecnica di Schlenk, polimerizzazione UV,
sintesi solvo- ed idrotermale)
1.Sintesi di oxocluster tetranucleari di zirconio Zr4
2.Sintesi di materiali ibridi organici-inorganici reticolati da oxocluster di zirconio Zr4
3.Sintesi di ferriti mediante coprecipitazione di ossalati e mediante sintesi idrotermale
4.Sintesi e caratterizzazione spettroscopica dei complessi di vanadile V(I) (d1)
5.Chimica di coordinazione del Cu(II)
6.Sintesi biogenica di nanostrutture colloidali di argento
7.Complesso polinucleare termocromico di Cu(I)
8.Polimeri di coordinazione a base di Cu(II)
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Polymerisation
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
basic concept
incorporation of a basic structure of one material (guest) in a second one
(matrix) combination and synergy of the properties
+
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
polymer
flexibility
formability, processability
low density, lightness
inorganic
hardness
thermal stability
high refractive index
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
guest host
(matrix)
example of
guest
inorganic organic nanoparticles,
whiskers, fibers,
lamellae, clusters
organic inorganic polymers,
biomolecules,
enzymes, dyes
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
guest host
(matrix)
example of
guest
inorganic organic nanoparticles,
whiskers, fibers,
lamellae, clusters
organic inorganic polymers,
biomolecules,
enzymes, dyes
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Class I Class II
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
simple embedding of organic and inorganic compounds only weak bonds
(van der Waals, hydrogen) link the two phases
A: dissolution of molecules - dyes, catalytically active metal complexes,
sensor compounds, biomolecules, enzymes, antibodies - or dispersion of particles
in the precursor solution: the gel matrix is formed around them and traps them
B: sol-gel processing of alkoxides performed in a solution of an organic polymer,
the inorganic network and the organic network interpenetrate but they are not
bonded to each other
Class I
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Class IIthe two constituents are linked together through strong (covalent or ionic)
chemical bonds. Examples are
1- in silicate systems it is possible to use R’Si(OR)3 molecules as sol-gel
precursors. In the organically substituted derivatives the R’ group is bonded
through a Si-C link to the network-forming inorganic part of the molecule
Since Si-C bonds are hydrolitically stable, the organic groups are retained
in the final materials.
2- interpenetrated dual network by formation of chemical bonds
3- polymers reinforced by covalently bonded inorganic clusters
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
1. overcoming of the structural limits of conventional materials (polymers, ceramics, metals
etc.)
2. fine tuning of the properties through variation of:
- composition
- microstructure
- interaction at the interface
3. design of multifunctionality (combination of functionalities)
4. infinite compositional variability
advantages of I/O hybrid materials
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Fundamental textbooks
Clement Sanchez, Pedro Gomez Romero
Functional Hybrid Materials
VCH Wiley, Weinheim, Germany 2004
Ulrich Schubert, Nicola Hüsing
Synthesis of inorganic materials
VCH Wiley, Weinheim, Germany, 2004
Guido Kickelbick
Hybrid Materials
VCH Wiley, Weinheim, Germany 2006
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Polymerisation
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Experimental parameters
Cluster type (M= Zr, Hf, Ta)
Cluster: monomer molar ratios (1: 25, 1: 50, 1: 100, 1: 200)
Polymerisation type (photo- or thermoactivated)
Monomer nature (MMA, MA, styrene, HEMA)
Nature of the final samples (thin films or bulk specimen)
Film deposition method (spray, spin, dip-coating)
+ monomer hybrid
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
free radical polymerisation
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
free radical
polymerisation
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
free radical polymerisation
photoactivated thermoactivated
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
UV radiation photoinitiator
reactive species monomer, oligomer
cured polymer
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Initiation RM.
R.h
IM
Propagation RM.i + M RM
.i+1
RM.n RM
.k
+ RMn+k R
RMn
+ RMk
Termination
photochemical initiators
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
photochemical initiators: requirements
• High photosensitivity in the range of wavelength 300–400 nm.
• Good solubility and reactivity in the oligomer–monomer system.
• Guarantee of the stability during storage and environmental tests
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
photochemical initiators: requirements
C
O
C
OR
h .C
O
C
OR
.+
..
H
C
O
C
OR'
OCHR
. .+C
O
C
OR'
OCH2R
C
O
C
OR'
OCH2R
C
O
C
R
R
OH C
O
C
R
R
OH+..
C P
O O
C
O
P
O
+..
Benzilketals
Dialkoxyacetophenones
Hydroxyalkylphenyl ketones
Benzoyol phosphine oxides
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
photochemical
initiators: examples
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Chemical identity Melting point ( °C)UV/VIS absorption peaks (nm) in
methanol
IRGACURE-184 1-Hydroxy-cyclohexyl-phenyl-ketone MP 45–49 246, 280, 333
IRGACURE-651Alpha-dimethoxy-alpha-
phenylacetophenoneMP 64–67 254, 337
IRGACURE-819Bis (2,4,6-trimethylbenzoyl)-
phenylphosphineoxideMP 127–133 370, 405
IRGACURE-9072-Methyl-1 [4-(methylthio)phenyl]-2-
morpholinopropan-1-oneMP 70–75 232, 307
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
high-intensity, medium pressure mercury vapor lamp
The emission from this type of unit is rich in UV radiation in the 200-400 nanometer band
This energy is in the area suited to the proper and complete curing as most
UV curable products incorporate photoinitiators which react within this bandwidth
UV lamps
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
UV lamps: emission spectrum
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
UV lamps: depth of curing
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
Lampade UV e sicurezza (vedere sezione “Sicurezza”
sito didattica docente)
Norme Europee e Norme principali
EN166 requisiti di base
EN167 metodi per test ottici
EN168 metodi per test non ottici.
EN169 filtri per saldatura
EN170 filtri per UV
EN171 filtri per IR
EN172 filtri solari per utilizzo industriale
Quando si usa la lampada UV:
- No mani nude sotto la lampada (400 W)
- Sempre occhiali protezione UV forniti
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
REFERENCES ON PHOTOPOLYMERISATION
“Radiation Curing in Polymer Science and technology”, Vol. I-IV, J.P. Fouassier, J.F. Rabek
ed., Elsevier London, 1993.
“Photopolymerization and Ultraviolet Curing of Multifunctional Monomers”, C. Decker,
Materials Science and technology, H.E.H. Meijer ed., VCH, Germany, 1997.
“Radiation Curing Science and Technology”, S.P. Pappas Ed., Plenum Press, New York, 1992.
“Photoinitiators for Free Radical Cationic and Anionic Photopolymerization”, J.V. Crivello, p.
329, G. Bradley ed., Wiley, New York, , 2nd ed., 1998.
“Photopolymerization of surface coatings“ C.G. Roffey, Wiley, New York, 1982.
“Photoinitiated Crosslinking Polymerization” C. Decker, Progress in Polymer Science, Vol. 21,
593, 1996.
“Cationic Photopolymerization” R. Lazauskaite, J.V. Grazulevicius, Handbook of
Photochemistry and Photobiology, H.S. Naiwa ed., Vol.2, Chapt. 7, p. 335, American Scientist
Publisher, New York, 2003.
“The discovery and Development of onium salt cationic photoinitiators” J.V. Crivello, Journal
of Polymer Science Polymer Chemistry, Vol. 37, p. 4241, 1999.
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. Synthesis of Zr-hybrid materials
photopolymerisation kinetics
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. characterisation of hybrid materials
- FT-IR (on PMMA and hybrid material)
- swelling (on PMMA and hybrid material)
- TGA-DSC (on 3 selected samples, PMMA and 2 hybrids)
→ comparison hybrid/PMMA
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. characterisation of hybrid materials
swelling behaviour
the swelling behaviour in polymeric materials is generally used for the
characterization of elastomeric networks
Operative modeThe simple experiment consists in completely immersing a sample in a solvent and in
waiting until swelling equilibrium occurs. An accurate value can be obtained only with
samples which have been carefully extracted to remove soluble materials. The
swollen network is reweighted and the weight percentage increase provides the
extent of swelling and a good phenomenological characterization of the polymer.
The swelling index (Isw) can be calculated according to:
Isw (g/g) = (wet weight - dry weight)/ dry weight
and it corresponds to the weight of the solvent that the dry material is able to absorb
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. characterisation of hybrid materials
swelling behaviour
Swelling results from two competitive
thermodynamic phenomena:
(i) the entropy increase of the system network-solvent due to the introduction
of small particles as diluent;
(ii) the decrease of the polymeric chain entropy due the isotropic expansion.
Equilibrium is reached as soon as the maximum swelling is obtained.
A statistical treatment of Gibbs free energy function, DG, affords a qualitative
relationship between the swelling and the degree of the crosslinking
density, which can be profitably used to characterize polymeric materials.
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. characterisation of hybrid materials
swelling behaviour
low solvent uptake
low swelling
high crosslinking
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
2. characterisation of hybrid materials
swelling behaviour
2.0
1.5
1.0
0.5
clu
ste
r p
rop
ort
ion
[m
ol
%]
4.54.03.53.02.52.01.51.00.50.0
solvent uptake [g solvent/g polymer]
Z r4
O2
(O M c )1 2
T a4
O4
(O M c )4
(O Et )8
T i4
O2
(O P ri)
6(O M c )
6 Ta4O4(OEt)8(OMc)4
Ti4O2(OPri)6(OMc)6
Zr4O2(OMc)12
OMc = methacrylate
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
thermogravimetric analysis
Operative mode
continuous weighting of a small sample (ca 10 mg) in a controlled atmosphere (e.g.,
air or nitrogen) as the temperature is increased at a programmed linear rate
typically at a constant rate, in the range 1-20°C/min
an electromagnetic balance having a typical sensitivity of 0.1 micrograms is used to
measure the weight variations
Possibility to interface the thermal analysis equipment with other instruments (IR,
GC-MS…)
measures the change of weight of a sample as a function of
either time or temperature
2. characterisation of hybrid materials
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
100
80
60
40
20
0
wei
gh
t lo
ss (
%)
800700600500400300200100
temperature (°C)
DT=80°C
PMMATa4PMMA50Ta4PMMA100Ta4PMMA200
2. characterisation of hybrid materials
Silvia Gross - Chimica Inorganica III - Laurea Magistrale in Chimica
Application to polymer science and hybrid materials
• TA is a very simple technique for quantitatively analysing the
filler/inorganic content of a polymer compound (Zr-based oxocluster in
PMMA ZrO2)
• it allows to investigate the decomposition path of the materials as well
as the actual content of inorganic component
• purity control
• stability as a function of the inorganic content
thermogravimetric analysis
2. characterisation of hybrid materials