SAMPE Journal - July/August 2022 - 60

FEATURE / BENZOXAZINE FORMULATION
Co-polymerization of Benzoxazine and Epoxy
Resin
Two epoxy resins were used for this investigation,
one is Huntsman Araldite GY 285 , another is Araldite
MY610. The first is a difunctional epoxy resin
derived from bisphenol F, the latter is a trifunctional
resin derived from meta-aminophenol. A 1:1
ratio weight ratio of benzoxazine and epoxy resin
applied. DSC scan result show in following Table 3.
Two of those commercial benzoxazines 35610
and 35700 has a small exotherm peaks around
160°C all DSC with GY285 show two separated
peaks, along with PPA derived benzoxazine. In the
Furfural amine benzoxazine series, there could
also be more than one peak, but those peaks are
not separated. Compared to the benzoxazine
resin itself, when mixed with epoxy resin, the peak
temperature is increased for both propargyl amine
benzoxazines, and furfuryl amine benzoxazines,
However, for resin without functional group, the
peak temperature is slightly decreased. An example
of those change could be seen in Figure 2.
All samples were staged cured up to 220°C or
230°C. Unlike some of those homo-polymerized
materials, all copolymerization with epoxy resin
yielded a good dish casting, without out-gassing
problem. All DMA and TGA have been measured.
All storage moduli are close to one and another,
between 3-4 GPa at room temperature, and are
slightly higher when mixed with MY0610. When copolymerized
with GY285, Tg are all decrease. GY285
is a difunctional epoxy resin, the copolymerization
of benzoxazine and GY285 essentially reduced the
reaction between the furan rings or carbon-carbon
triple bond. The polymerized material would have
more linear region, and the cross-link density
reduced greatly. For the furfuryl amine, the benefit
come from the reaction between furan basically
disappeared, the Tg become essentially same as
the aniline benzoxazine and GY285 mixture. The
propargylamine fared a little better, the triple bond
still could react with some of those hydroxy group
that come from the ring opening of benzoxazine
or epoxy. When co-polymerized with MY0610, the
trifunctional epoxy resin, the case become more
complicated. Those trifunctional resin boosted
the Tg of those benzoxazines without additional
reactive functional group but reduce those having
it. All polymerized sample of aniline benzoxazine/
MY0610 mixture have higher Tg than the homopolymerized
aniline benzoxazines, the increased
is about 50 -60°C. For the propargyl amine
benzoxazine, the Tg more or less stay the same,
but they are decreased for those furfuryl amine
benzoxazines.
Resin
35610
35700
35900
5292B-PPA
BisA-PPA
BisM-PPA
5292B-FA
BisA-FA
BisF-FA
Thio-FA
TOnset (o
118
C)
TPeak1 (o
C)
TPeak2 (o
With GY285 (1:1 Weight Ratio)
168
222
125
232
170
174
151
159
153
190
156
186
250
157
255
210
215
206/245
208
198/243
229
230
218
276
275
269
260
258
35610
35700
35900
5292B-PPA
BisA-PPA
BisM-PPA
5292B-FA
BisA-FA
BisF-FA
Thio-FA
With MY0610 (1:1 Weight Ratio)
219
214
172
170
154
161
197
267
257
220
215
208
183
186
204
208
241
236
227
218
301
286
286
256
271
265
258
Table 3. DSC result of benzoxazine and epoxy mixture.
C)
∆ H (J/g)
42
274
54
243
333
556
727
627
334
315
213
416
392
432
504
650
756
570
560
381
471
416
Figure 2. DSC scan comparison.
60 | SAMPE JOURNAL | JULY AUGUST 2022
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SAMPE Journal - July/August 2022

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