FIBER REINFORCED THERMOPLASTIC MATRIX COMPOSITE MATERIAL
Fiber reinforced composite material comprising a thermoplastic matrix comprising blends of poly(ether ketone ketone) (PEKK) polymers, their method of manufacture and articles obtained therefrom.
1 . A composite material, comprising:
fibers, and
a thermoplastic polymer matrix comprising a composition [composition (C)] comprising a first and a second PEKK polymer each PEKK polymer characterised by a T/I ratio, wherein the T/I ratio of the first PEKK polymer is different from T/I ratio of the second PEKK polymer.
2 . The composite material of claim 1 in which composition (C) comprises a first PEKK polymer [(PEKK low )] having a T/I ratio [(T/I) low ], and a second PEKK polymer [(PEKK high )], having T/I ratio [(T/I) high ], such that (T/I) low <(T/I) high .
3 . The composite material of claim 1 wherein each PEKK polymer is a polymer comprising recurring units (R T ) and recurring units (R I ), wherein recurring unit (R T ) is represented by formula (T):
and recurring unit (R I ) is represented by formula (I):
wherein:
each R 1 and R 2 , at each instance, is independently selected from the group consisting of an alkyl, an alkenyl, an alkynyl, an aryl, an ether, a thioether, a carboxylic acid, an ester, an amide, an imide, an alkali or alkaline earth metal sulfonate, an alkyl sulfonate, an alkali or alkaline earth metal phosphonate, an alkyl phosphonate, an amine, and a quaternary ammonium; and
each i and j, at each instance, are integers independently selected from 0 to 4; and the T/I ratio is defined as:
(
T
/
I
)
=
T
I
wherein
:
T
(
mol
.
%
)
=
[
units
(
R
T
)
]
[
units
(
R
T
)
]
+
[
units
(
R
I
)
]
×
100
,
and
I
(
mol
.
%
)
=
[
units
(
R
I
)
]
[
units
(
R
T
)
]
+
[
units
(
R
I
)
]
×
100.
4 . The composite material of claim 3 wherein (PEKK high ) has a molar content of units (R T ), (T high ), and (PEKK low ) has a molar content of units (R T ), (T low ), such that T high −T low ≤20 mol. %.
5 . The composite material of claim 2 wherein (T/I) low is at least 50/50, and/or at most 64/36.
6 . The composite material of claim 2 wherein (T/I) high is at least 65/35, and/or at most 85/15.
7 . The composite material of claim 2 wherein the weight ratio between polymer (PEKK low ) and polymer (PEKK high ) is of at least 60/40, and/or it is of at most 99/1.
8 . The composite material of claim 2 wherein polymer (PEKK low ) and/or polymer (PEKK high ) is a nucleophilic PEKK polymer.
9 . The composite material of claim 1 wherein composition (C) is characterized by one or more of the features selected from the group consisting of:
a crystallization temperature (Tc in C°), determined on second DSC heat scan, higher than the crystallization temperature of a PEKK polymer having the same melting temperature (T m in) C°) determined on second DSC heat scan;
a melting temperature (T m ) of less than or equal to 330° C., a heat of fusion (ΔHf) exceeding 25 J/g; and no crystallization peak upon heating, on second DSC heat scan (“cold crystallization peak”);
a relation between melting temperature (T m in ° C.) determined on second DSC heat scan, and crystallization temperature (T c in ° C.) determined on first DSC cooling scan, which satisfies the following inequality: T c ≥1.3716×T m −190° C.;
wherein T m , T c , ΔHf and the absence of cold crystallization peak are measured by differential scanning calorimetry (DSC) according to ASTM D3418-03, E1356-03, E793-06, E794-06, standard, applying heating and cooling rates of 20° C./min, with a sweep from 300° C. to 400° C.
10 . The composite material of claim 1 wherein composition (C) further comprises at least one nucleating agent.
11 . The composite material of claim 1 wherein composition (C) has a melting temperature (Tm) of less than or equal to 330° C.
12 . The composite material of claim 1 wherein the fiber is a continuous fiber and/or is selected from the group consisting of carbon fibers, graphite fibers, glass fibers, ceramic fibers, synthetic polymer fibers, polyimide fibers, high-modulus polyethylene (PE) fibers, polyester fibers and polybenzoxazole fibers, aramid fibers, boron fibers, basalt fibers, quartz fibers, alumina fibers, zirconia fibers and mixtures thereof.
13 . The composite material of claim 1 exhibiting at least one of:
an open hole compression strength greater than or equal to 320 MPa, as measured in accordance with ASTM D6484; and
an in-plane shear modulus of greater than or equal to 4.7 GPa, as measured in accordance with ASTM D3518.
14 . A multilayer composite assembly comprising a first layer consisting of the composite material of claim 1 and at least one layer comprising a thermoplastic polymer composition [composition (TP)] in contact with at least one surface of the composite material.
15 . A method of making the composite material of claim 1 , the method comprising contacting the polymer matrix comprising composition (C) with at least a part of the surface of the fibers.
16 . The method of claim 15 , wherein the polymer matrix is contacted with fibers in a melt impregnation process, in slurry process, in a film lamination process or in dry powder coating/fusion process.
17 . A method for making a low void, consolidated laminate, the method comprising:
processing layers of the composite material of claim 1 with an automated lay-up machine outfitted with a heat device to simultaneously melt and fuse a layer to a previously-laid layer as the layer is being placed and oriented on the previously-laid layer to form a consolidated laminate having less than 2% volume of voids; and
optionally further comprising annealing the consolidated laminate in either a free standing or vacuum bag operation, typically in temperature range of 170° C. to 270° C. for a time from 1 minute to 240 minutes.
18 . A method for forming a composite part, the method comprising:
pre-orienting plies of the composite material of claim 1 ,
consolidating the pre-oriented plies in a heated and cooled press, double belt press or continuous compression molding machine to make a consolidated laminate;
optionally cutting the consolidated laminate to a pre-determined size to make a forming blank;
rapidly heating the forming blank to a temperature of 320 to 360 C in a stamp-forming process tool, thus making a formed composite part.
19 . A consolidated laminate, composite part, article comprising a composite material of claim 1 .