Synthesis, characterization, and properties of new phosphorus-containing epoxy resins

Article abstract of DOI:10.1080/10426507.2011.583616

Four new phosphonate-epoxy monomers were synthesized and characterized by ¹H and ³¹P-NMR, matrix-assisted laser desorption/ ionization time-of-flight mass spectrometry (MALDI-TOF MS), thermal gravimetric analysis (TGA), and different

Full text of DOI:10.1080/10426507.2011.583616

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Phosphorus, Sulfur, and Silicon and the
Related Elements
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Synthesis, Characterization, and
Properties of New Phosphorus-
Containing Epoxy Resins
Salvatore Failla a , Paolo Finocchiaro a , Giuseppe A. Consiglio a ,
Filippo Samperi b , Salvatore Battiato b & Andrea Scamporrino b
a Dipartimento di Metodologie Fisiche e Chimiche per l’Ingegneria,
Facoltà di Ingegneria , Università di Catania , Viale A. Doria, 6.,
I-95125, Catania, Italy
b Institute of Chemistry and Technology of Polymers (ICTP) – Sez.
Catania, CNR , Via Gaifani 18, 95126, Catania, Italy
Published online: 31 Oct 2011.
To cite this article: Salvatore Failla , Paolo Finocchiaro , Giuseppe A. Consiglio , Filippo Samperi ,
Salvatore Battiato & Andrea Scamporrino (2011) Synthesis, Characterization, and Properties of New
Phosphorus-Containing Epoxy Resins, Phosphorus, Sulfur, and Silicon and the Related Elements,
186:11, 2189-2201, DOI: 10.1080/10426507.2011.583616
To link to this article: http://dx.doi.org/10.1080/10426507.2011.583616
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Phosphorus, Sulfur, and Silicon, 186:2189–2201, 2011
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2011.583616
SYNTHESIS, CHARACTERIZATION, AND PROPERTIES
OF NEW PHOSPHORUS-CONTAINING EPOXY RESINS
Salvatore Failla,1 Paolo Finocchiaro,1 Giuseppe A. Consiglio,1
Filippo Samperi,2 Salvatore Battiato,2
and Andrea Scamporrino2
1Dipartimento di Metodologie Fisiche e Chimiche per l’Ingegneria, Facolta` di
Ingegneria, Universita` di Catania, Viale A. Doria, 6. I-95125 Catania, Italy
2Institute of Chemistry and Technology of Polymers (ICTP) – Sez. Catania, CNR,
Via Gaifani 18, 95126 Catania, Italy
GRAPHICAL ABSTRACT
Abstract Four new phosphonate-epoxy monomers were synthesized and characterized by 1H
and 31P-NMR, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry
(MALDI-TOF MS), thermal gravimetric analysis (TGA), and differential scanning calorimetry
(DSC) tools. Beside the expected compund, the formation of a small amounts of linear oligomers
was also observed by MALDI-TOF MS. These monomers were used to prepare new phosphorus-
containing epoxy resins in order to obtain potential flame retardant polymers. The thermal
behavior of these new epoxy resin was studied by DSC, TGA, and direct pyrolysis mass
spectrometry (DPMS). TGA and DPMS data show that either the maximum decomposition
temperature (PDT) or the onset of the thermal degradation of the phosphorus-containing
epoxy resins is lower than that of the corresponding nonphosphonate samples.
Keywords Phosphonate epoxy resin; MALDI-TOF MS; chemical characterization
INTRODUCTION
The most commonly used approach for enhancing the fire safety performance of
polymeric materials is the use of flame retardant additives. Although halogenated flame
retardants are highly effective for reducing the heat release rate of polymers, problems such
Received 11 March 2011; accepted 20 April 2011.
Partial financial support from the National Council of Research (CNR, Rome) and from Italian Ministry for
Univeristy and Research (MIUR) is gratefully acknowledged. The active collaboration of Mr. Pastorelli Gaetano
and Dr. Carbone Domenico to part of this work, in particular for their pertinent technical support, is acknowledged.
Address correspondence to Salvatore Failla, Dipartimento di Metodologie Fisiche e Chimiche per
l’Ingegneria, Facolta` di Ingegneria, Universita` di Catania, Viale A. Doria, 6. I-95125 Catania, Italy. E-mail:
sfailla@dmfci.unict.it
2189

2190
S. FAILLA ET AL.
as poor compatibility, leaching, reduced mechanical properties, and environmental impact
of certain halogenated flame retardants limit their application.1
Demands for flame retardant epoxy resins are extremely high because of their wide
application in adhesives, coatings, and advanced composites in aerospace and electronic
industries.1 The most effective way to improve flame retardancy in epoxy resin is the
reactive approach: incorporating phosphorus-containing chemical units into the polymer
backbone or side chain. Thus, while flame retardancy is increased, the original physical and
mechanical properties are retained. Moreover, it is essential that flame retardant systems
meet the requirement of new regulations, and the development of new halogen-free epoxy
resins is attracting considerable interest.2
Research has shown that the addition of relatively small amounts of phosphonate
compounds to epoxy resins has a flame retardant effect.3 This is partly due to the fact that
phosphonic residues can form a barrier to the advancing flame. These compounds mostly
perform their flame retardant function in the condensed phase by increasing the amount of
carbonaceous residue by the formation of a surface layer of protective char. Phosphorus,
like nitrogen and silicon, is regarded as an environmentally friendly flame retardant because
it can reduce the harmful impact on the environment.
Phosphorus-containing components have already been used in the synthesis of several
flame retardant step reaction polymers.1–4 However, their use in the synthesis as monomers
is much less well developed; there exists a need to develop the synthesis of new monomers
containing reactive selected functional groups in order to introduce phosphorus derivatives
into polymer chains.
In a previous article,5 we reported the syntheses of new phosphonated derivatives
of bis-phenols and used them to reduce the flammability of thermosetting diglycidyl ether
of bisphenol-A Di-Glycidyl Ether of Bisphenol-A (DGEBA) epoxy resin.6–8 Recently we
were involved in the synthesis of some bis-benzyl aminobenzyl phosphonates derivatives9
and a new aromatic diamine phosphonates monomer10 that could be used as a hardener
in the curing process of thermosetting epoxy resins or as a comonomer for the synthesis
of polyamides, to limit the flammability of the resulting systems. Therefore, considering
the interest and the wide application in reactive phosphorus-containing compounds as
antiflammable agents, we wish to report now the synthesis of some new monomers 5–8 that
contain the C–P bonds and use one of them for the synthesis of new phosphorus-containing
epoxy resin in order to investigate their flame retardance behavior.
Such monomers are of great relevance for the synthesis of novel macrocycles and
for polycondensates containing phosphonate moieties. More intriguing, phosphonate 8 is
a preorganized dissymmetric molecule and thus exist as a pair of enantiomers; it follows
that monomer 8 can be used as a chiral template that provides the necessary symmetry
conditions for building chiral polycondensates or inducing chirality in replicating strands.
RESULTS AND DISCUSSION
Synthesis of Phosphonate-Epoxy Monomers
The new phosphorus-containing epoxy monomers 5–8 reported in Scheme 1 were
prepared by condensation reaction using aromatic phosphonates phenols 1–4, which were
already synthesized by Finocchiaro et al.,5 and a large excess of epichlorihydrin at refluxing
temperature for 2 h, then stirred with 3 M solution of sodium hydroxide to give monomers
5–8. The condensation synthetic procedure used proved to be very satisfactory and all

NEW PHOSPHORUS-CONTAINING EPOXY RESINS
2191
PO3Et2
PO3Et2
Et2O3P
HO
a, b
Et2O3P
OH
O
O
O
(1)
(5)
O
O
SO2
SO2
Et2O3P
HO
PO3Et2
a, b
Et2O3P
PO3Et2
OH
O
(2)
(6)
O
O
O
O
OH
OH
PO3Et2
PO3Et2
a, b
Et2O3P
Et2O3P
O
(3)
(7)
O
a, b
Et2O3P
Et2O3P
PO3Et2
PO3Et2
OH
OH
O
O
(4)
(8)
O
O
Scheme 1
monomers were obtained as oil, for the presence of little amount of oligomers, in almost
quantitative yield.
Interesting enough, monomer 5 represents the phosphonate analog of the commercial
DGEBA, which is the most common monomer used for the synthesis of epoxy resins. The
use of monomer 5 in the industrial synthetic process does not require any modification of
the plant because of similar reactivity of DGEBA, and thus it could be added as needed for
modulating the self-extinguish properties of the manufactured articles.
All the new monomers were characterized by 1H, 31P NMR, and matrix-assisted laser
desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The 500 MHz
1H NMR spectrum of the isolated crude oil at room temperature in CDCl3 solution, obtained
from the reaction outlined in Scheme 1 for monomer 5, shows a triplet (δ = 1.31) and a
multiplet (δ = 4.15) for the ethoxy groups linked to the phosphorus atoms, a sharp singlet
(δ = 1.64) for the methyl groups attacked to the methylene bridged carbon, a multiplet
(δ = 2.90) for the Hd and He methylene protons, a multiplet (δ = 3.37) for the Hc methyne
proton, a doublet of doublet (δ = 4.02–4.04) for the Ha methylene proton, a doublet of

2192
S. FAILLA ET AL.
Table 1 1H NMR shifts∗ of the epoxy group hydrogens and 31P NMR shifts∗ of the synthesized monomers
Hc
C
Ha
Hd
He
Ar
O
C
C
Hb
O
Ha
Hb
Hc
Hd, He
31P NMR
Monomer
(δ, ppm)
(δ, ppm)
(δ, ppm)
(δ, ppm)
(δ, ppm)
5
6
7
8
4.04–4.02(dd)
4.11–4.08(dd)
4.10–4.00(dd)
3.89–3.83(m)
4.33–4.31(dd)
4.48–4.35(dd)
4.39–4.37(dd)
3.37(m)
3.38(m)
3.37(m)
3.32(m)
2.91–2.87(m)
2.91–2.89(m)
2.89–2.87(m)
2.89–2.87(m)
17.32
13.40
14.77
17.95; 17.91
Hidden by ethoxy moiety
∗δ are given in ppm.
doublet (δ = 4.31–4.33) for the Hb methylene proton, and three signals for the aromatic
protons with the expected multiplicity.
Comparing the proton chemical shifts values of the epoxy moiety of compounds
5–8 reported in Table 1, only small change, due to the identical connection of the epoxy
group to the aromatic ring, is observed. On the contrary, a significant change in chemical
shifts value is observed in the 31P{H} NMR spectra. In fact, the phosphorus signal of
monomers 5 and 8 are present at 17.32 and 17.95 ppm respectively, whereas in compounds
6 and 7, it appears at 13.40 and 14.77 ppm, respectively. No doubt this difference is due
to the effect of the different electronic environments in the aromatic rings. However, a
significant change in chemical shift values between the starting phosphonate phenols and
the corresponding monomers is observed in the 31P{H} NMR spectra. As an example,
in phenol 1, the phosphorus signal is present as a singlet at δ = 21.24 ppm,5 whereas in
monomer 5, the 31P signal still appears as a singlet but resonate at δ = 17.32 ppm. This
difference is due to the presence of a strong intramolecular hydrogen bond present in 1
involving the phenolic OH and the adjacent P O group; this interaction is not present after
the formation of the epoxy ether groups.
Characterization of phosphonate-epoxy monomers 5–8 was also performed by
MALDI-TOF MS,11,12 which confirmed that the condensation reaction gives rise to a
linear compounds with small amount of oligomers, as can be observed in Figure 1 that
shows their mass spectra recorded in reflectron mode by using dithranol as matrix and
CF3COONa salt as cationizating agent. It also shows the structure of each compound that
appears as sodiated ions [M+Na+] in the MALDI-TOF mass spectra.
Since the MALDI-TOF mass spectra give unambiguous information on the chemical
structure of the products, and the relative intensity of the corresponding mass peaks reflects
the molar fraction of each component of the analyzed mixture, we have calculated the mol%
of the monomers and oligomers present in the samples 5–8 using the relative intensities
of the sodiated molecular ions from the corresponding mass spectra (Figure 1). Sample 5
presents 75% of expoxy monomer, 22% of dimer, and 3% of trimer; sample 6 present 91%
of monomer and 9% of dimer; sample 7 is constituted of 77% of monomer and 23% of
dimer; 33% of monomer, 20% of dimer and 3% of trimer are present in the sample 8.

NEW PHOSPHORUS-CONTAINING EPOXY RESINS
2193
Figure 1 MALDI-TOF mass spectra of sample: (a) 5; (b) 7; (c) 8. Each molecular species appears as sodiated
ions [M + Na+] in the corresponding mass spectrum.
Adduct of the epoxy sample with the 2-(4-hydroxyphenylazo)benzoic acid (HABA),
used as matrix (MM 243.2), was also observed. In fact, besides the mass peaks due to
the sodiated ions of the epoxy species discussed above, the MALDI mass spectra showed
additional peaks at m/z M+243 which indicated that the epoxy groups react with the
carboxyl moiety of HABA during the preparation of the sample for MALDI analysis.

2194
S. FAILLA ET AL.
Table 2 MALDI-TOF MS molecular weight, calculated and found Epoxy Equivalent Weight for compounds
5–8
Monomer
MW
MALDI-TOF MW
EEW calculated
EEW found
5
6
7
8
612.59
634.57
494.41
692.71
340.42
612.8
634.8
494.7
693.1
340.7
306.3
317.3
247.2
346.3
170
296
302
257
323
178
DGEBA
Note: MW, molecular weight.
Moreover, in order to estimate the epoxy groups, the epoxy equivalent weight (EEW)
of each monomer was determined by titration, and the result are reported in Table 2. It
reveals that the synthetic pathway chosen and reported in Scheme 1 gives rise to monomers
with a little amount of oligomers. In fact, due to the presence of these oligomers, the EEW
values found are smaller than the calculated.
Synthesis of Expoxy Copolymers
Resin plaques were prepared by mixing epoxy compounds with an equivalent amount
of the curing agent at room temperature. The formulations reported in Table 3 were heated
to 80 ◦C with stirring until it became homogeneous, degasse◦d at the same temperature◦in
a vacuum oven for 10 min, then were cured for 5 h at 110 C, and postcured at 180 C
for 1 h.
The curing of all systems shown in Table 3 was followed by differential scanning
calorimetry (DSC) analysis. It reveals that for all formulations the cross-linking occurs at
about 212–213 ◦C independent of the DGEBA/phophonated-epoxy monomers ratio.
Thermal Degradation Behavior
The thermal degradation behaviors of the epoxy copolymer reported in Table 3 have
been assessed by dynamic thermal gravimetric analysis (TGA) in nitrogen and air at a
◦
heating rate of 10 C/min. The TG curves are given in Figure 2. Clearly, the thermal
degradation behavior of the phosphorus-containing polymers is significantly different to
that of the homopolymer F1. In fact, under a nitrogen atmosphere (see Figure 2a), a one-
step degradation mechanism is observed, and when monomer 5 or 6 are present in small
Table 3 Feed composition for the preparation of epoxy copolymers
Formulation
DER 332a
3,3ꢁDDSa
Monomera
F1
F2
F3
F4
F6
10
9.5
9.0
9.5
9.0
10
10
10
10
10
—
(5) 0.5
(5) 1.0
(6) 0.5
(6) 1.0
Note: D.E.R.TM 332 Dow Epoxy Resin is a high purity bisphenol A diglycidylether. DDS 3,3ꢁ-DiaminoDiphenyl
Sulfone.
aAmount are given in equivalent × 10−3
.

NEW PHOSPHORUS-CONTAINING EPOXY RESINS
2195
Figure 2 TGA curves of samples F1, F2, and F3 in Table 3, recorded under (a) N2 and (b) air flow.
percentage (i.e., F2, F4), the maximum decomposition rate shifts to lower temperatures
and that shift depends on the amount of phosphorus-containing monomer.
◦
The F2–F6 copolymers start to decompose above 330 C, but with a much ◦lower
rate than the homopolymer F1 (DGEBA/DSS) that starts to decompose above 360 C. A
relatively stable carbonaceous residue or char is formed during the heating in N2 and the
char yields at 800 ◦C were different for the different formulations (i.e., 14% for F1, 26%
for F3).
TGA of the copolymer performed in air (see Figure 2b) shows that degradation
occurs roughly at the same temperature as the degradation in nitrogen, but in the case of
degradation in air, the TG curve has two peaks that are not observed in nitrogen.
The thermal degradation of epoxy copolymers was also studied by direct pyrolysis
mass spectrometry (DPMS). Here we report some preliminary DPMS data obtained using
an 18-eV electron impact (EI) i◦onization source and a heating rate of 10 ◦C/min. EI mass
spectra recorded at about 320 C show intense peak at m/z 28 may be due to ethylene

2196
S. FAILLA ET AL.
(CH2 CH2) formed by degradation of ethylene phosphonate units, and also a peak at
m/z 45 corresponding to the [CH3CHOH]+ ions produced by degradation of ethylene
phosphonate groups. The presence of these peaks suggest, as reported before, that the
initial degradation step of the phosphonate copolymers involves the phosponate groups, as
confirmed by DPMS analysis of the monomers 5–8.13 Ion fragments produced owing to the
degradation mechanisms of the macromolecular chains of the samples F1–F6 are present
◦
in the EI-DPMS spectra recorded at a probe temperature higher than 350 C, and their
structures will be discussed in the next article together with the mechanisms that generate
it.13 In this article, we will discuss the primary pyrolysis products formed during the thermal
degradation of monomers 5–8, of their epoxy copolymers, and also the mechanisms that
allow their formation. In this work, we shall also report the characterization of the char
structures and the flammability properties of these epoxy copolymers.
Further evidence of the intumescent nature of the char obtained from the phosphonate-
modified resins is given by scanning electron microscopy (SEM). Figures 3a and 3b show
SEM micrographs of the basic (F1) and phosphonate resin (F3), respectively. It is evident
that the char surface obtained from formulation F3, containing 10% of monomer 5, is a
porous fragmented shape (see Figure 3b) as compared with a smooth and compact shape of
char obtained from the nonmodified polymer F1 (see Figure 3a). The multicellular surface
consists of agglomerates of swollen particles, which are typical of foamed intumescent
chars.
Flame Resistance
A flame resistance test was performed by placing a cured epoxy cylindrical specimen,
approximately 5 cm long with a diameter of 0.5 cm, in a propane torch flame at a 45◦ angle
for 5–10 s and noting the time required for the sample to self-extinguish upon removal from
the flame. Initially the burn test consisted of placing a cylinder piece of the crude resin in
the flame of propane torch for 5 s. As work progressed, the time in the propane torch flame
was increased to 10 s. No noticeable difference was detected between 5 and 10 s burns with
specimens from the same cylinder.
FT-IR Analysis
The phosphorus-containing epoxy resins where also characterized by Fourier trans-
form infrared (FT-IR) analysis and in Figure 4 are reported the spectra of nocross-linked
initial resin (system F1 in Table 3) and that of cross-linked resin with 10% of phosphorus
compound 5 (system F3 in Table 3). For comparison, the FT-IR spectrum of the cross-linked
system, obtained using 100% of monomer 5, is also reported in Figure 4c. In Figure 4,
we can observe that relative intensities of the absorption bands at 1024 and 967 cm−1 due
to the stretching of the P O and –PO– groups, respectively, increase as raise the amount
of the monomer 5 in the epoxy resins. This data confirm that the phosphorus compound
is covalently linked with the epoxy resins, since the same FT-IR spectra were obtained
for the cross-linked materials treated with tetrahydrofuran (THF), which is a good sol-
vent for phosphorous compounds 5–8. Very similar FT-IR spectra were obtained for the
phosphorus-containing epoxy resins F4 and F6 mentioned in Table 3.

NEW PHOSPHORUS-CONTAINING EPOXY RESINS
2197
Figure 3 SEM pictures of the char obtained from (a) the basic system F1 and (b) the phosphonate resin F3.

2198
S. FAILLA ET AL.
(c)
(b)
(a)
4000
3500
3000
2500
1600
1400
1200
1000
800
600
Wavenumber (cm-1)
Figure 4 FT-IR spectra of epoxy resins obtained with (a) 0%, (b) 10%, and (c) 100% equivalent of phosphonate-
epoxy monomers 5.
CONCLUSIONS
New kinds of epoxy resins were prepared from phosphonate-epoxy monomers 5–8
and appropriately synthesized. These new monomers were accurately characterized by
1H and 31P NMR and MALDI-TOF MS techniques. The MALDI-TOF mass spectra of
the crude epoxy monomers reveal the presence also of small amount of linear oligomers
(generally dimers and trimers). The epoxy resins were characterized by FT-IR, TGA, and
DPMS tools. TGA studies, under dynamic N2 or air atmosphere, reveal that the onset
of the thermal degradation of the phosphonated epoxy resins is lower with respect to
that of corresponding no-phosphonated material. This behavior depends on the amount of
phosphorus-containing monomer.
EXPERIMENTAL
Materials
All reactions were performed under an inert atmosphere of nitrogen, and the solvents
were refluxed and freshly distilled before use. Toluene was dried by distillation from sodium
under a nitrogen atmosphere. Compounds 1–4 were prepared according to a published
procedure.5 Epichlorohydrin was supplied by Alfa and DEER-32 (DGEBA) by Aldrich.
Unless otherwise stated, commercial chemicals were used as supplied.

NEW PHOSPHORUS-CONTAINING EPOXY RESINS
2199
Aldrich Chemical Co. supplied the reagents and solvents used. The reagents were
purified before use. The MALDI matrices HABA and 1,8-dihydroxy-10H-anthracen-9-
one (dithranol) were analytical-grade materials (Sigma Aldrich Chemical Co.), used as
supplied.
Characterization
EEW were determined using the hydrogen bromide method.14
Char surface morphology was examined by field emission scanning electron mi-
croscopy (FE-SEM) using a ZEISS SUPRA VP 55 microscope.
NMR Spectroscopy. The 1H and 31P NMR spectra were recorded in a solution of
CDCl3 at 25 ◦C by a Varian-Inova instrument operating at 500 and 200 MHz, respectively,
using tetramethylsilane (TMS) as internal reference and H3PO4 (85%) as external reference.
All 31P NMR spectra are decoupled from the proton. All the chemical shifts are reported in
parts per million with respect to the used reference.
The data were enhanced with 1D Win-NMR software by applying the Lorentz–Gauss
function using appropriate line broadening and Gaussian broadening parameters in order
to improve the peaks resolutions.
MALDI-TOF Mass Spectrometry. MALDI-TOF mass spectra were recorded in
linear and reflectron modes, using a Voyager-DE STR instrument (Perseptive Biosystem)
mass spectrometer, equipped with a nitrogen laser (λ = 337 nm, pulse width = 3 ns),
working in a positive ion mode. The accelerating voltage was 25 kV; grid voltage and delay
time (delayed extraction, time lag) were optimized for each sample to achieve the higher
mass resolution [full width at half maximum (FWHM)]. Laser irradiation was maintained
slightly above the threshold. Dithranol and HABA were used as matrices. Samples used for
the MALDI analyses were prepared as follows. Ten microliter of each epoxy sample (3–
5 mg/mL in THF) were mixed with 30 µL of matrix solution (0.1 M in THF). This solution
was added to 1 µL of 0.01 M solution of CF3COONa salt as cationizating agent, in THF
solvent. Then 1 µL of each analyte–matrix–salt mixture was spotted on the MALDI sample
holder and slowly dried to allow analyte/matrix co. The better MALDI mass spectra were
obtained in reflectron mode using dithranol as a matrix and present a mass resolution of
about 3000–4000, expressed as the molar mass of a given ion divided by the FWHM. The
accuracy of mass determination was about 90 ppm in the mass range of 500–2000 Da.
Differential Scanning Calorimetry. The cross-linking of epoxy copolymers
F1–F6 in Table 3 was studied by a Mettler DSC 20 calorimeter coupled with a Met-
tler TC 10A processor as a control and evaluation unit. Both heat flow and temperature
calibrations of calorimeter were performed following the procedures suggested by the
supplier and reported in the operating instructions of the equipment. For all samples, the
cross-linking occured at about 212–213 ◦C.
Thermogravimetry. TGA were performed by a calibrated TA Instruments TGA
◦
◦
◦
Q500 at a heating rate of 10 C/min from 50 C up to 800 C under nitrogen flow
(60 mL/min), using 2–3 mg of sample. The weight and temperature of the instrument
were calibrated using a high-purity magnetic standard for the Curie temperature and some
exact weights following both calibration procedures through the instrument control soft-
ware. The TGA data were analyzed by a TA Instruments operating software.
DPMS. Mass spectra were obtained using a Fisons QMD 1000 mass spectrometer
equipped with the Lab-base software and quadrupole analyzer. Pyrolysis was carried out
◦
using the water-cooled direct insertion probe for solid materials, heated from 100 C up

2200
S. FAILLA ET AL.
to 700 ◦C at heating rate of 10 ◦C/min, using 1–2 mg of each sample. Mass spectra were
continuously acquired at a scan rate of 2 s (from 10 to 1000 Da), interscan time 2. EI mass
spectra were obtained at 18 eV. The source temperature was maintained at 260 ◦C, and the
acceleration voltage was 8 kV.
Synthesis
General Synthetic Procedure for bis-epoxy monomers 5–8 (Scheme 1): To epichloro-
hydrin (32 mL, 400 mmol) were added phenols 1–4 (20 mmol), and to this clear solution,
an aqueous solution containing 60% of benzyl-triethyl ammonium chloride (45.5 mg) was
added. Then the mixture was refluxed under a nitrogen atmosphere for 2 h. After cooling
the mixture to 50 ◦C, an aqueous solution of 3 M NaOH (10 mL) saturated with Na2CO3
was added and stirred for 1 h. After cooling at room temperature, CHCl3 was added and the
organic phase was washed several times with aqueous saturated solution of NaCl and then
with water until of a neutral pH. After drying over Na2SO4, the solvent of the organic phase
was evaporated and a colorless oil was collected and stored under a nitrogen atmosphere.
Data for compound 5: 2,2-bis(3-diethylphosphono-4-epoxyetherphenyl)-propane.
1
Colorless oil, 11.64 g (95%). MALDI-TOF MS; m/z: 635.8 (100) [M + Na]+. H NMR
3
4
(CDCl3, ppm) δ = 7.70 (2 H, dd, JHP = 16.0 Hz, JHH = 2.5 Hz, ArH), 7.24 (2 H, dd,
3JHH = 8.5 Hz, 4JHH = 2.5 Hz, ArH), 6.83 (2 H, dd, 4JHP = 7.5 Hz, 3JHH = 8.5 Hz, ArH),
4.32 (2 H, m, ArOCH2), 4.16 (8 H, m, POCH2CH3), 4.07 (2 H, m, ArOCH2), 3.36 (2 H,
m, CH epoxy), 2.90 (4 H, m, CH2 epoxy), 1.64 (6 H, s, CCH3), 1.32 (12 H, t, 3JHH = 7.0
Hz, POCH2CH3). 31P NMR (CDCl3, ppm) δ = 17.29.
Data for compound 6, bis-(3-diethylphosphono-4-epoxyetherphenyl) sulfone. Color-
less oil, 5.71 g (45%). MALDI-TOF MS; m/z: 657.8 (100) [M + Na]+. 1H NMR (CDCl3,
ppm) δ = 8.30 (2 H, dd, 3JHP = 15.0 Hz, 4JHH = 2.5 Hz, ArH), 8.06 (2 H, dd, 3JHH = 8.5
4
4
3
Hz, JHH = 2.5 Hz, ArH), 7.05 (2 H, dd, JHP = 6.0 Hz, JHH = 8.5 Hz, ArH), 4.46 (2
H, m, ArOCH2), 4.18 (8 H, m, POCH2CH3), 4.10 (2 H, m, ArOCH2), 3.37 (2 H, m, CH
epoxy), 2.91 (4 H, m, CH2 epoxy), 1.36 (12 H, t, POCH2CH3, 3JHH = 7.0 Hz). 31P NMR
(CDCl3, ppm) δ = 13.40.
Data for compound 7: 1,4-diethylphosphono-2,5-epoxyether-benzene. Yellowish
1
solid, 8.01 g (81%). MALDI-TOF MS; m/z: 517.7 (100) [M + Na]+. H NMR (CDCl3,
ppm) δ = 7.46 (2 H, dd, 3JHP = 15.5 Hz, 4JHP = 7.5 Hz, ArH), 4.37 (2 H, m, ArOCH2),
4.19 (8 H, m, POCH2CH3), 4.02 (2 H, m, ArOCH2), 3.37 (2 H, m, CH epoxy), 2.88 (4 H,
m, CH2 epoxy), 1.35 (12 H, t, 3JHH = 7.0 Hz, POCH2CH3). 31P NMR (CDCl3, ppm) δ =
14.63.
Data for compound 8, bis-(5,5ꢁ-diethylphosphono)-6,6ꢁ-diepoxyether-3,3,3ꢁ,3ꢁ-
tetramethyl-1,1ꢁ-spirobiindane. Yellowish solid, 13.58 g (98%). MALDI-TOF MS; m/z:
715.9 (100) [M + Na]+. 1H NMR (CDCl3, ppm) δ = 7.62 (2 H, m, ArH), 6.27 (2 H, m,
ArH), 4.22 (10 H, m, ArOCH2 + POCH2CH3), 3.87 (2 H, m, ArOCH2), 3.32 (2 H, m,
CH epoxy), 2.85 (4 H, m, CH2 epoxy), 2.26 (4 H, m, spirobiindane CH2), 1.38 (18 H, m,
spirobiindane CH2 + POCH2CH3), 1.33 (s, 6 H, spirobiindane CH3). 31P NMR (CDCl3,
ppm) δ = 17.95, 17.91.
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