POLYMERIC MATERIALS

Abstract

A blend comprising: (i) a polymeric material (A) having a repeat unit of formula

—O—Ph—O—Ph—CO—Ph—  I

and a repeat unit of formula

—O—Ph—Ph—O—Ph—CO—Ph—  II

wherein Ph represents a phenylene moiety; and (ii) a polymeric material (B) having a repeat unit of formula (XX)

##STR00001##

wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

Claims

1. A blend comprising: (i) a polymeric material (A) having a repeat unit of formula
—O—Ph—O—Ph—CO—Ph—  I and a repeat unit of formula
—O—Ph—Ph—O—Ph—CO—Ph—  II wherein Ph represents a phenylene moiety; and (ii) a polymeric material (B) having a repeat unit of formula (XX) ##STR00007## wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

2. A blend according to claim 1, wherein said repeat unit of formula I has the structure ##STR00008## and said repeat unit of formula II has the structure ##STR00009##

3. A blend according to claim 2, wherein said polymeric material (A) includes at least 62 mol % (e.g. at least 64 mol %) of repeat units of formula III; and at least 10 mol % (e.g. at least 18 mol %) of repeat units of formula IV.

4. A blend according to claim 2, wherein polymeric material (A) includes 58-82 mol % of units of formula III and 18-42 mol % of units of formula IV.

5. A blend according to claim 1, wherein the Tm of said polymeric material (A) is less than 330° C., for example less than 310° C.; and preferably is greater than 280° C.

6. A blend according to claim 1, wherein polymeric material (B) has a repeat unit wherein t1=1, v1=0 and w1=0.

7. A blend according to claim 1, wherein polymeric material (B) consists essentially of a repeat unit of a formula XX, preferably such a repeat unit wherein t1=1, v1=0 and w1=0.

8. A blend according to claim 1, wherein the difference between the MV of polymeric material (A) and polymeric material (B) is less than 0.3 kNsm.sup.−2, more preferably less than 0.15 kNsm.sup.−2, when MV is measured at 400° C. as described in Example 3.

9. A blend according to claim 1, wherein the blend comprising polymeric material (A) and polymeric material (B) has a crystallinity measured by one or both of the Example 4 method or WAXS as described of at least 30% or at least 33%.

10. A blend according to claim 1, wherein the polymeric material (A) and the polymeric material (B) define a combination (which is preferably a substantially homogenous mixture) which exhibits a single Tm and/or a single Tg.

11. A blend according to claim 1, wherein, in the blend, the difference between the Tm and Tg is in the range 155° C. to 185° C.

12. A blend according to claim 1, wherein, in the blend, the Tm is less than 330° C. and the Tg is greater than 148° C.

13. A blend according to claim 1, wherein said blend is part of a composition which includes said blend and a filler.

14. A blend according to claim 13, wherein said composition includes 50-90 wt % of said blend and 10-50 wt % of filler.

15. A blend according to claim 1, which includes a polymeric material (C) having a repeat unit of formula ##STR00010##

16. A blend according to claim 1, wherein the blend comprises thermoplastic polymers in the absence of filler and the blend is in the form of pellets or granules.

17. A method of improving the fracture toughness of a polymeric material (B) having a repeat unit of formula (XX) ##STR00011## wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2, the method comprising: (a) selecting polymeric material (B); (b) selecting a polymeric (A) having a repeat unit of formula
—O—Ph—O—Ph—CO—Ph—  I and a repeat unit of formula
—O—Ph—Ph—O—Ph—CO—Ph—  II wherein Ph represents a phenylene moiety; and (c) blending polymeric material (A) with polymeric material (B).

18. A method according to claim 17, wherein said polymeric material (A) has a crystallinity of at least 15, preferably at least 27%; and said polymeric material (B) has a crystallinity of at least 30%.

19. A method according to claim 17, wherein, after step (c), the blend has a crystallinity of at least 30%.

20. A method according to claim 17, wherein polymeric material (A) has a repeat unit of formula
—O—Ph—O—Ph—CO—Ph—  I and a repeat unit of formula
—O—Ph—Ph—O—Ph—CO—Ph—  II wherein Ph represents a phenylene moiety and polymeric material (B) has a repeat unit of formula (XX) ##STR00012## wherein t1 and w1 independently represent 0 or 1 and v1 represents 0, 1 or 2.

21. A method of making a composition which comprises: (i) selecting a filler; (ii) contacting the filler with a blend as described according to claim 1.

22. The use of a polymeric material (A) as described according to the first and/or second aspects for improving the fracture toughness of a polymeric material (B) as described according to claim 1.

23. A pack comprising a blend as described in claim 1.

24. A component which comprises a blend or composition according to claim 1.

Description

EXAMPLE 1

Preparation of 0.5 mol polyetheretherketone (PEEK)—polyetherdiphenyletherketone (PEDEK) copolymer

[0092] A 0.5 litre flanged flask fitted with a ground glass lid, stirrer/stirrer guide, nitrogen inlet and outlet was charged with 4,4′-diflurobenzophenone (111.29 g, 0.510 mol), 1,4-dihydroxybenzene (41.30 g, 0.375 mol), 4,4′-dihydroxydiphenyl (23.28 g, 0.125 mol) and diphenylsulphone (241.07 g) and purged with nitrogen for 1 hour. The contents were then heated under a nitrogen blanket to 160° C. to form an almost colourless solution. While maintaining a nitrogen blanket, dried sodium carbonate (53.00 g, 0.5 mole) and potassium carbonate (2.76 g, 0.02 mol), both sieved through a screen with a mesh size of 500 micrometres, were added. The temperature was raised to 185° C. at 1° C./min and held for 100 minutes. The temperature was raised to 205° C. at 1° C./min and held for 20 minutes. The temperature was raised to 315° C. at 1° C./min and held at this temperature until the desired MV was reached as indicated by the torque rise on the stirrer. The required torque rise was determined from a calibration graph of torque rise versus MV. The reaction mixture was then poured into a foil tray, allowed to cool, milled and washed with 2 litres of acetone and then with warm water at a temperature of 40-50° C. until the conductivity of the waste water was <2 μS. The resulting polymer powder was dried in an air oven for 12 hours at 120° C. The MV of the resulting polymer was 0.60 kNsm.sup.−2 measured according to example 3 at 400° C. and the crystallinity was 21% measured according to Example 4.

EXAMPLE 2

Preparation of polyetheretherketone (PEEK)—polyetherdiphenyletherketone (PEDEK) copolymer

[0093] A 300 litre vessel fitted with a lid, stirrer/stirrer guide, nitrogen inlet and outlet was charged with diphenylsulphone (125.52 kg) and heated to 150° C. Once fully melted 4,4′-diflurobenzophenone (44.82 kg, 205.4 mol), 1,4-dihydroxybenzene (16.518 kg, 150 mol) and 4,4′-dihydroxydiphenyl (9.311 kg, 50 mol) were charged to the vessel. The contents were then heated to 160° C. While maintaining a nitrogen blanket, dried sodium carbonate (21.368 kg, 201.6 mol) and potassium carbonate (1.106 kg, 8 mol), both sieved through a screen with a mesh of 500 micrometres, were added. The D50 of the sodium carbonate was 98.7 μm. The temperature was raised to 180° C. at 1° C./min and held for 100 minutes. The temperature was raised to 200° C. at 1° C./min and held for 20 minutes. The temperature was raised to 305° C. at 1° C./min and held until desired melt viscosity was reached, as determined by the torque rise of the stirrer. The required torque rise was determined from a calibration graph of torque rise versus MV. The reaction mixture was poured via a band caster into a water bath, allowed to cool, milled and washed with acetone and water. The resulting polymer powder was dried in a tumble dryer until the contents temperature measured 112° C. The MV of the resulting polymer was 0.15 kNsm.sup.−2 measured according to Example 3 at 400° C. and the crystallinity was 29% measured according to Example 4.

EXAMPLE 3

Determination of Melt Viscosity (MV) of Polymer

[0094] Unless otherwise stated, this was measured using capillary rheometry operating at 340° C. or 400° C. (as specified) at a shear rate of 1000 s.sup.−1 using a circular cross-section tungsten carbide die, 0.5 mm (capillary diameter×3.175 mm (capillary length). The MV measurement was taken 5 minutes after the polymer had fully melted, which is taken to be 5 minutes after the polymer is loaded into the barrel of the rheometer.

EXAMPLE 4

Differential Scanning Calorimetry of Polyaryletherketones of Examples

[0095] Crystallinity described herein may be assessed by several methods for example by density, by IR spectroscopy, by x ray diffraction or by differential scanning calorimetry (DSC). The DSC method has been used to evaluate the crystallinity that developed in the polymers from Examples 1 and 2 using a Mettler Toledo DSC1 Star system with FRS5 sensor.

[0096] The Glass Transition Temperature (Tg), the Melting Temperature (Tm) and Heat of Fusions of Melting (AHm) for the polymers were determined using the following DSC method.

[0097] A dried sample of each polymer was compression moulded into an amorphous film, by heating 7 g of polymer in a mould at 400° C. under a pressure of 50 bar for 2 minutes, then quenching in cold water producing a film of dimensions 120×120 mm, with a thickness in the region of 0.20 mm. An 8 mg plus or minus 3 mg sample of each film was scanned by DSC as follows: [0098] Step 1 Perform and record a preliminary thermal cycle by heating the sample from 30° C. to 400° C. at 20° C./min. [0099] Step 2 Hold for 5 minutes. [0100] Step 3 Cool at 20° C./min to 30° C. and hold for 5 mins. [0101] Step 4 Re-heat from 30° C. to 400° C. at 20° C./min, recording the Tg, Tn, Tm, ΔHn and ΔHm.

[0102] Tc is measured on the cooling cycle (Step 3) and is the temperature at which the crystallisation exotherm reaches a minimum.

[0103] From the DSC trace resulting from the scan in step 4, the onset of the Tg was obtained as the intersection of the lines drawn along the pre-transition baseline and a line drawn along the greatest slope obtained during the transition. The Tn was the temperature at which the main peak of the cold crystallisation exotherm reaches a maximum. The Tm was the temperature at which the main peak of the melting endotherm reached a maximum.

[0104] The Heat of Fusion for melting (AHm) was obtained by connecting the two points at which the melting endotherm deviates from the relatively straight baseline. The integrated area under the endotherm as a function of time yields the enthalpy (mJ) of the melting transition: the mass normalised heat of fusion is calculated by dividing the enthalpy by the mass of the specimen (J/g). The level of crystallisation (X(%)) is determined by dividing the Heat of Fusion of the specimen by the Heat of Fusion of a totally crystalline polymer, which for polyetheretherketone and for the PEEK-PEDEK copolymer is 130 J/g and for the PPSU containing blend of Example 15 is 91 J/g. Note that PPSU is amorphous and does not contribute to the crystallisation peak in the DSC trace. The value of 91 J/g is based on a blend containing 30 wt % of PPSU and 70 wt % of PEEK and/or PEEK-PEDEK. Thus, the Heat of Fusion is 70%×130 J/g=91 J/g.

EXAMPLE 5

General Procedure for Preparing Blends

[0105] Blends were prepared by compounding on a Rondol 10 mm Twin Screw Extruder operating with a die temperature of 360° C., barrel temperature of 340° C.-360° C. and with a screw speed of 84 rpm. The polymer powders were mixed and then added to the extruder via a hopper using a ‘powder’ screw feed; polymer granules were obtained at a throughput of 196 g per hour.

EXAMPLE 6

General Procedure for Injection Moulding of Polymers for Fracture Toughness Testing

[0106] ASTM impact test bars were moulded on a Boy 12A injection moulding machine with a tool temperature of 220° C., barrel temperature of 360° C.-400° C. and nozzle temperature of 400° C. with a screw speed of 10 mm/s. The holding pressure was 80-95 bar.

EXAMPLE 7

General Procedure for Testing Fracture Toughness

[0107] Fracture toughness was measured using a 3-point bend test on an Instron 5567 tensometer with 30KN load cell according to a modified ASTM D 5045-99 test method. The test was modified such that an ASTM flex support (51 mm span) and anvil were used with a crosshead speed of 100 mm/min using a machine notched sample.

[0108] Results

[0109] Blends made using VICTREX 650G and the PEEK-PEDEK copolymer of Example 1 were tested.

[0110] Results are provided in Table 1 below.

TABLE-US-00001 TABLE 1 PEEK in Blend composition Fracture Example PEEK/PEDEK (wt %) Energy Tg Tm X Tc No's (mol fraction) PEEK/PEDEK PEEK (KJm.sup.−2) (° C.) (° C.) (%) (° C.)  8* 1.00 0 100 15.8 147 338 40 284 9 0.65 25 75 15.9 151 333 34 278 10  0.65 50 50 17.3 151 327 33 271 11  0.75 75 25 16.5 155 315 36 251 12* 0.90 100 0 15.5 149 322 32 259 13* 0.85 100 0 14.3 150 314 29 248 14* 0.80 100 0 15.9 152 305 24 231 *refers to comparative examples

[0111] The results show that the blends of Examples 9 to 11 exhibit both high fracture energy and high crystallinity. The combination of properties is improved compared to PEEK alone (Example 8) and PEEK-PEDEK alone (Examples 12 to 14). In addition, the Tm of the blends of Examples 9 to 11 is lower than the Tm of PEEK meaning the blends can be processed at lower temperatures. Additionally, the Tg of the blends is higher than for PEEK meaning the blends will advantageously retain mechanical properties at higher temperatures than for PEEK. Furthermore, the Tc of the blends is lower than for PEEK meaning that injection moulded parts can be made from the blends which have less in-built stress. This may make the blends advantageous for some applications, for example gears. In addition, the blend may be useful in production of thick-walled pipes, since such a pipe may be made with high crystallinity but with reduced built in stress (and so increased fracture toughness).

[0112] As an alternative to blends comprising only PEEK and the PEEK-PEDEK copolymer described in Example 9 to 11, blends may be made comprising the aforesaid and PPSU as described below.

EXAMPLE 15

Preparation of PEEK/PEEK-PEDEK/PPSU Blends

[0113] The blends were prepared by compounding VICTREX 150G, the PEEK-PEDEK copolymer of Example 2 and PPSU on a ZSK25 Twin Screw Extruder with a die temperature of 365° C., barrel temperature of 350° C.-360° C. and a screw speed of 250 rpm. The polymer powders were mixed and then added to the extruder via a hopper using a ‘powder’ screw feed, with a screw speed of 150 rpm; polymer granules were obtained at a throughput of 12 Kg per hour.

EXAMPLE 16

General Procedure for Injection Moulding of PEEK/PEEK-PEDEK/PPSU Blends for Fracture Toughness Testing

[0114] ASTM impact test bars were moulded on a Boy 12A injection moulding machine with a tool temperature of 195° C., barrel temperature of 360° C.-400° C. and nozzle temperature of 400° C. with a screw speed of 10 mm/s. The holding pressure was 35 bar.

[0115] Results

[0116] Characteristics of the blends of Examples 17 to 19 were assessed as described in Example 4 and results are provided in Table 2.

TABLE-US-00002 TABLE 2 PEEK in Blend composition Fracture Example PEEK/PEDEK (wt %) Energy Tm X Tc No. (mol fraction) PEEK/PEDEK PEEK PPSU (KJm.sup.−2) Tg (° C.) (° C.) (%) (° C.) 17* n/a 0 70 30 1.33 147 338 36 285 18* 0.75 70 0.00 30 2.35 154 303 23 244 19  0.75 35 35 30 2.22 148 328 31 272 *refers to comparative examples

[0117] Referring to Table 2, it will be noted that both the fracture energy and crystallinity of the PEEK/PEEK-PEDEK/PPSU blend of Example 19 are higher than for a blend of PEEK and PPSU and for a blend of PEEK-PEDEK and PPSU.

[0118] The blends described may have wide-ranging applications where high fracture toughness and high crystallinity is required.

[0119] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.