CN101062970A - Polysiloxane toughening allyl group linear pnenolic aldehyde/bimaleimide resin - Google Patents

Abstract

The invention discloses polysiloxane toughened allyl novolac/bismaleimide resin, which can be prepared by the following method: (1) hydrogen-blocked polydimethylsiloxane 1 and hydrogen-blocked Mix the terminal polydimethylsiloxane 2 with the allyl novolac resin solution evenly, and react at 50°C to 80°C under the action of a catalytic amount of metal catalyst to obtain polysiloxane toughened allyl novolak Resin; (2) bismaleimide monomer is joined in the product of step (1), refluxes in solvent, obtains polysiloxane toughened allyl novolac/bismaleic acid after solvent removal imide resin. The resin of the invention has good process performance, and compared with the pure allyl novolac/bismaleimide resin system, the impact strength is greatly improved, the heat resistance is equivalent, and the preparation method is simple, and it can be used for the matrix of high-performance composite materials resin.

Description

Polysiloxane toughened allyl novolak/bismaleimide resin

technical field

The present invention relates to allyl novolac/bismaleimide resin, in particular to polysiloxane toughened allyl novolac/bismaleimide resin.

Background technique

Phenolic resin is widely used in aerospace, transportation and many other fields due to its good heat resistance and thermal ablation. However, the bulk viscosity of phenolic resin is high, and a large amount of low-molecular substances are released during the curing process, so that the traditional phenolic resin cannot meet the requirements of the resin transfer molding (RTM) process. Moreover, the brittleness of the cured phenolic resin is also relatively large, which limits the scope of use of the phenolic resin to a certain extent. The introduction of allyl groups into the molecular structure of phenolic resins can not only reduce the viscosity of the resin, making it suitable for the requirements of the RTM molding process; Reaction, bismaleimide (BMI) with outstanding comprehensive properties is introduced into the molecular structure of phenolic resin. The allyl novolac/BMI resin system has more excellent heat resistance and greatly improved mechanical properties, and is expected to become a matrix resin for high-performance composite materials. However, there are a large number of benzene ring structures in the molecular structure of the allyl novolac/BMI resin system and the cured product has a very high crosslinking density. Therefore, the toughness of the allyl novolac/BMI resin cured product still needs to be further improved . The polysiloxane molecular main chain has excellent flexibility and good heat resistance, and is a good modifier for modifying thermosetting resins. However, polysiloxane has poor compatibility with general organic polymers, so it is very important to improve the compatibility between them. Using functionalized polysiloxane as a modifier, introducing polysiloxane into the molecular structure of organic polymers through the reaction between functional groups can improve the compatibility between the two to a certain extent. Tsung-Han Ho et al. introduced hydrogen-functional polysiloxane into the novolac epoxy resin system to reduce the thermal stress of the system and achieved good results, but did not mention the impact of the introduction of polysiloxane on the toughness of the resin system [1. Polymer 38(1997), 1997-2003; 2. European Polymer Journal 37(2001), 267-274].

Contents of the invention

The object of the present invention is to provide polysiloxane toughened allyl novolak/bismaleimide resin.

The present invention adopts two-component polysiloxane as a toughening modifier, utilizes hydrosilicon addition reaction, and links allyl novolac resin molecular chains with polysiloxane molecular chains through chemical bonds to provide a polysiloxane Alkane toughened allyl novolac/BMI resin. Among them, the components with smaller molecular weight are used as compatibilizers to improve the compatibility of polysiloxane and allyl novolac resin, and expand the molecular weight range of polysiloxane that can be used. The resin has good process performance, and compared with the pure allyl novolac/BMI resin system, the impact strength is greatly improved, the heat resistance is equivalent, and the preparation method is simple.

The allyl novolak/bismaleimide resin of polysiloxane toughening of the present invention can adopt following method to prepare:

(1) A solution containing 1 to 5 parts by weight of hydrogen-terminated polydimethylsiloxane 1 and 5 parts by weight of hydrogen-terminated polydimethylsiloxane 2 and 90 to 94 parts by weight of allyl novolac resin Mix evenly, and react at 50° C. to 80° C. under the action of a catalytic amount of metal catalyst (preferably 4 to 12 hours), to obtain polysiloxane toughened allyl novolac resin.

The general formula of the hydrogen-terminated polydimethylsiloxane is:

Among them, the number of repeated chains of hydrogen-terminated polydimethylsiloxane 1 is 6≤p≤8, and the number average molecular weight is 500-800; the number of repeated chains of hydrogen-terminated polydimethylsiloxane 2 is 20≤ p≤40, the number average molecular weight is 1500-3000.

The structural formula of described allyl novolac resin is:

Wherein, m+n>1, and the number average molecular weight ranges from 550 to 900.

The solvent of the allyl novolak resin solution may be toluene, 4-methyl-2-pentanone or tetrahydrofuran.

The metal catalyst can be an isopropanol solution of H ₂ PtCl ₆ or a xylene solution of H ₂ PtCl ₆ .

The molar concentration of the isopropanol solution of H ₂ PtCl ₆ is 0.004-0.008M;

The content of Pt in _the xylene solution of _H2PtCl6 is 3-5wt%;

For the preparation of the xylene solution of H ₂ PtCl ₆ , refer to literature: JVCrivello et al., Journal of Polymer Science: Part A: Polymer Chemistry 24 (1986), 1197-1215.

(2) Add bismaleimide monomer to the product of step (1), wherein the molar ratio of maleimide group to allyl group is 0.3～0.6:1; reflux in solvent (preferably 1 to 2 hours), and obtain polysiloxane-toughened allyl novolac/bismaleimide resin after removing the solvent. The solvent can be 4-methyl-2-pentanone or butanone.

The structural formula of described bismaleimide monomer is:

The synthesis reference of the allyl novolac resin: Yehai Yan, et al., Journal of Applied Polymer Science 83 (2002), 1651-1657.

References for the synthesis of the hydrogen-terminated polydimethylsiloxane: Chen Li, master's degree thesis, Institute of Chemistry, Chinese Academy of Sciences, 1994. Using concentrated sulfuric acid as a catalyst and tetramethyldisiloxane (M ^H M ^H ) as an end-capping agent, octamethylcyclotetrasiloxane (D ₄ ) was ring-opened and polymerized to obtain hydrogen-terminated polydimethylsiloxane Oxane; adjusting the ratio of octamethylcyclotetrasiloxane to tetramethyldisiloxane can obtain hydrogen-terminated polydimethylsiloxane 1 or hydrogen-terminated polydimethylsiloxane with different molecular weights, respectively alkane 2. Wherein the concentration of the concentrated sulfuric acid of the catalyst is 95-98%, and the dosage is 1-5wt% of the mass of octamethylcyclotetrasiloxane; the reaction temperature is 10-30°C; octamethylcyclotetrasiloxane and tetramethylsiloxane The relationship between the ratio (molar ratio) and the number average molecular weight of base disiloxane is shown in the table below: Number average molecular weight 750 1700 3000 D ₄ : M ^H M ^H 1:1 4.6:1 7.3:1

The method adopted in the structural characterization of the present invention is nuclear magnetic resonance method (including ¹ H-NMR, ²⁹ Si-NMR). The mechanical performance characterization method of the present invention adopts the impact strength test (according to ISO179-1982 (E)). The method adopted in the heat resistance characterization of the present invention is thermogravimetric analyzer (TGA), wherein the 5% weight loss temperature of TGA and the mass retention rate of 900° C. characterize the heat resistance performance.

The invention uses hydrogen-terminated polydimethylsiloxane as a modifier to improve the toughness of the allyl novolac/BMI resin system. Experimental results show that. Polysiloxane can improve the toughness of allyl novolac/BMI resin system. However, there are strict requirements on the molecular weight of polysiloxane, otherwise, it is difficult to obtain a satisfactory toughening effect. The present invention adopts two-component polysiloxane as toughening modifier, wherein, polysiloxane of small molecular weight is used as compatibilizer, improves the compatibility of polysiloxane of large molecular weight and matrix resin, expands usable Molecular weight range of polysiloxane.

The advantage that the resin that the present invention obtains compared with existing resin is:

(1) The present invention improves the compatibility of polysiloxane and allyl novolac resin by adding polysiloxane with smaller molecular weight, expands the molecular weight range of polysiloxane that can be used, and obtains Transparent, stable allyl novolak resin containing polysiloxane segments. The resin has good process performance, the viscosity is equivalent to that of pure allyl novolak resin, and meets the requirements of RTM process.

(2) adopt the allyl novolac/bismaleimide resin cast body impact strength of the polysiloxane toughening prepared by the present invention to have significant improvement compared with pure allyl novolak/BMI resin, and impact strength is higher The unmodified resin is increased by 2-2.6 times, and at the same time, the heat resistance is basically the same as that of pure allyl novolac/BMI resin. Matrix resins for high performance composites.

Detailed ways

Example 1

Step 1: Add 90.00g (0.21mol) of novolac resin and 135g of n-butanol into a 500ml three-necked flask equipped with mechanical stirring, condenser and thermometer, and add 29.87g (0.44mol) of potassium hydroxide after the novolak resin is completely dissolved , After reacting for 2h, 42.41g (0.44mol) of allyl chloride was added dropwise, and reacted for 6h. After the reaction is completed, filter while it is hot, collect the filtrate and remove the solvent with a rotary evaporator to obtain an allyl novolac resin.

The structure was characterized by ¹ H-NMR:

¹ H-NMR (using deuterated dimethyl sulfoxide containing TMS as a solvent, and the chemical shift of dimethyl sulfoxide at 2.5 ppm as a standard): 7.1, 7.0, 6.9, 6.8 ppm phenyl (phenyl), 6.0 , 5.9ppm (Φ-OCH ₂ CH=CH ₂ and Φ-CH ₂ CH=CH ₂ ), 5.2, 5.4ppm (Φ-OCH ₂ CH=CH ₂ ), 4.95ppm (Φ-CH ₂ CH=CH ₂ ) , 4.5 ppm (Φ-OCH ₂ CH=CH ₂ ), 3.9, 3.8, 3.7 ppm (Φ-CH ₂ -Φ), 3.3 ppm (Φ-CH ₂ CH=CH ₂ ).

The number average molecular weight was 707 calculated from the integrated areas at 3.7-3.9 ppm, 4.95 ppm and 5.2-5.4 ppm in ¹ H-NMR.

Step 2: Add 200.00g (0.68mol) of octamethylcyclotetrasiloxane (D ₄ ) and 19.56g (0.15mol) of tetramethyldisiloxane (M ^H M ^H ) into a 500ml three-neck flask equipped with mechanical stirring ), fully stirred evenly; under vigorous stirring, 6.32g of concentrated sulfuric acid was added dropwise, and reacted at 30°C for 6h; 3.79g of deionized water was added, and the reaction was continued for 6h. After the reaction stopped, the reaction solution was transferred to a separatory funnel, the acid layer was separated, and then washed with a large amount of deionized water until pH = 7; finally, the low boiler was removed by vacuum distillation to obtain a hydrogen-terminated poly Dimethicone (2).

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 0.08ppm[(CH ₃ ) ₂ SiO], 0.19ppm[HSi(CH ₃ ) ₂ ], 4.71 ppm (SiH).

²⁹ Si-NMR (deuterated acetone containing TMS as solvent, TMS chemical shift at 0 ppm as standard): -5.47ppm (Si-H), -18.58ppm, -20.54ppm [(CH ₃ )SiO].

The number average molecular weight of the above-mentioned polydimethylsiloxane (2) was calculated as 1700 based on the integral areas at 0.08 ppm and 0.19 ppm in ¹ H-NMR.

Step 3: Add 40.00g (0.14mol) of octamethylcyclotetrasiloxane (D ₄ ) and 18.09g (0.14mol) of tetramethyldisiloxane (M ^H M ^H ) into a 250ml three-neck flask equipped with mechanical stirring ), fully stirred evenly; under vigorous stirring, 0.4 g of concentrated sulfuric acid was added dropwise, and reacted at 25° C. for 6 h; 0.76 g of deionized water was added, and the reaction was continued for 6 h. After the reaction stopped, the reaction solution was transferred to a separatory funnel, the acid layer was separated, and then washed with a large amount of deionized water until pH = 7; finally, the low boiler was removed by vacuum distillation to obtain a hydrogen-terminated poly Dimethicone (1).

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 0.08ppm[(CH ₃ ) ₂ SiO], 0.19ppm[HSi(CH ₃ ) ₂ ], 4.71 ppm (SiH).

²⁹ Si-NMR (deuterated acetone containing TMS as solvent, TMS chemical shift at 0 ppm as standard): -5.47ppm (Si-H), -18.58ppm, -20.54ppm [(CH ₃ )SiO].

The number average molecular weight of the aforementioned polydimethylsiloxane (1) was calculated to be 750 based on the integrated areas at 0.08 ppm and 0.19 ppm in ¹ H-NMR.

Step 4: Add allyl novolac resin 94.00g (0.22mol) in a four-necked flask equipped with mechanical stirring, _N2 inlet, thermometer and spherical condenser, the above-mentioned number average molecular weight is 1700 hydrogen-terminated polydimethyl 5.00 g (0.0029 mol) of siloxane (2), 1.00 g (0.0013 mol) of hydrogen-terminated polydimethylsiloxane (1) with a number average molecular weight of 750, and 150.00 g of toluene were refluxed for 1 h under nitrogen protection; Then, the temperature was lowered to 25° C., and 2.52 ml of H ₂ PtCl ₆ in isopropanol was added, wherein the molar concentration of H ₂ PtCl ₆ in isopropanol was 0.0077M. Raise the temperature to 80°C and react for 4 hours; after the reaction, transfer the reaction liquid to a 500ml single-necked bottle, and remove the solvent with a rotary evaporator to obtain 5wt% polysiloxane with a number average molecular weight of 1700 and 1wt% number average molecular weight of 750 Alkane-modified allyl novolac resin, the appearance is wine red transparent liquid.

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 7.1, 7.0, 6.9, 6.8ppm phenyl (phenyl), 6.0, 5.9ppm (Φ-OCH ₂ CH=CH ₂ and Φ-CH ₂ CH=CH ₂ ), 5.2, 5.4ppm (Φ-OCH ₂ CH=CH ₂ ), 4.95ppm (Φ-CH ₂ CH=CH ₂ ), 4.5ppm (Φ-OCH ₂ CH=CH ₂ ), 3.9, 3.8, 3.7ppm (Φ-CH ₂ -Φ), 3.3ppm (Φ-CH ₂ CH=CH ₂ ), 1.8ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si), 0.7 ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si).

²⁹ Si-NMR (using deuterated acetone containing TMS as solvent, TMS chemical shift at 0ppm as standard): 9.58ppm (Φ-CH ₂ CH ₂ CH ₂ -Si and Φ-OCH ₂ CH ₂ CH ₂ -Si ), -19.63 ppm and -20.18 ppm [(CH ₃ ) ₂ SiO].

Step 5: Add 90.00 g (allyl group 0.60 mol) of the polysiloxane-containing allyl novolac resin obtained above to a 500ml three-necked flask equipped with mechanical stirring, a spherical condenser, and a thermometer, and bismaleyl 31.95 g of imine monomer (0.17 mol of maleimide group) and 280 ml of 4-methyl-2-pentanone were heated to reflux for 1 h, and then the solvent was removed by rotary evaporator to obtain polysiloxane-modified olefin Propyl novolac/BMI resin blend, its appearance is dark red transparent liquid.

Step 6: Pour the polysiloxane-modified allyl novolac resin/BMI blend obtained above into the mold, and carry out in a common oven according to the procedure of 160°C 4h+200°C 4h+250°C 6h Heat and solidify to obtain a resin cast body.

TGA analysis showed that the 5wt% weight loss temperature of the cured resin was 415.1°C, and the mass retention rate at 900°C was 33.90%. The impact test shows that the impact strength of the cast resin is 4.78kJ/m ² , which is twice the impact strength of the unmodified allyl novolac/BMI resin.

Example 2

Step 1: Same as Step 1 in Example 1.

Step 2: Same as step 2 in Example 1.

Step 3: Same as Step 3 in Example 1.

Step 4: Add allyl novolac resin 92.00g (0.22mol) in a four-necked flask equipped with mechanical stirring, N _inlet , thermometer and spherical condenser, the hydrogen-terminated polydimethyl 5.00 g (0.0029 mol) of siloxane (2), 3.00 g (0.0040 mol) of hydrogen-terminated polydimethylsiloxane (1) with a number average molecular weight of 750, and 150.00 g of 4-methyl-2-pentanone , refluxed for 1 h under the protection of nitrogen; then, lowered to 25° C., and added 2.00 ml of a xylene solution of H ₂ PtCl ₆ , wherein the content of Pt in the xylene solution was 3 wt%. Raise the temperature to 80°C and react for 6 hours; after the reaction, transfer the reaction solution to a 500ml single-necked bottle, and remove the solvent with a rotary evaporator to obtain 5wt% polysiloxane with a number average molecular weight of 1700 and 3wt% number average molecular weight of 750 Alkane-modified allyl novolac resin, the appearance is wine red transparent liquid.

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 7.1, 7.0, 6.9, 6.8ppm phenyl (phenyl), 6.0, 5.9ppm (Φ-OCH ₂ CH=CH ₂ and Φ-CH ₂ CH=CH ₂ ), 5.2, 5.4ppm (Φ-OCH ₂ CH=CH ₂ ), 4.95ppm (Φ-CH ₂ CH=CH ₂ ), 4.5ppm (Φ-OCH ₂ CH=CH ₂ ), 3.9, 3.8, 3.7ppm (Φ-CH ₂ -Φ), 3.3ppm (Φ-CH ₂ CH=CH ₂ ), 1.8ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si), 0.7 ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si).

²⁹ Si-NMR (using deuterated acetone containing TMS as solvent, TMS chemical shift at 0ppm as standard): 9.58ppm (Φ-CH ₂ CH ₂ CH ₂ -Si and Φ-OCH ₂ CH ₂ CH ₂ -Si ), -19.63 ppm and -20.18 ppm [(CH ₃ ) ₂ SiO].

Step 5: Add 85.00 g (allyl group 0.56 mol) of the polysiloxane-containing allyl novolak resin obtained above to a 500ml three-necked flask equipped with mechanical stirring, a spherical condenser and a thermometer, and bismaleyl Imine monomer 60.86g (maleimide group 0.34mol) and methyl ethyl ketone 280ml, heat reflux 1h, adopt rotary evaporator to remove solvent then, obtain polysiloxane-modified allyl novolac/BMI resin Blend, its appearance is dark red transparent liquid.

Step 6: Pour the polysiloxane-modified allyl novolak resin/BMI blend obtained above into a steel mold, follow the procedure of 160°C 4h+200°C 4h+250°C 6h, in an ordinary oven Heat curing was performed to obtain a resin cast body.

TGA analysis showed that the 5wt% weight loss temperature of the cured resin was 418.5°C, and the mass retention rate at 900°C was 34.14%. The impact test shows that the impact strength of the cast resin is 5.68kJ/m ² , which is 2.4 times that of the unmodified allyl phenolic/BMI resin.

Example 3

Step 1: Same as Step 1 in Example 1.

Step 2: Same as Step 2 in Example 1.

Step 3: Same as Step 3 in Example 1.

Step 4: in the four-necked flask that is equipped with mechanical stirring, N _inlet , thermometer, add allyl novolac resin 100.00g (0.24mol), the number average molecular weight obtained above is the hydrogen-terminated polysiloxane (2 )5.500g (0.0032mol), 5.5g (0.0073mol) of hydrogen-terminated polysiloxane (1) with a number average molecular weight of 750, and 150.00g of toluene, refluxed for 1h under the protection of nitrogen; then, lowered to 25°C, added H ₂ PtCl ₆ isopropanol solution 5.10ml, wherein the molar concentration of H ₂ PtCl ₆ isopropanol solution is 0.004M, raise the temperature to 80°C, and react for 6h; after the reaction, transfer the reaction solution to a 500ml single port In the bottle, remove the solvent with a rotary evaporator to obtain 5wt% polysiloxane-modified allyl novolac resin with a number average molecular weight of 1700 and 5wt% number average molecular weight of 750, the appearance of which is a wine red transparent liquid.

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 7.1, 7.0, 6.9, 6.8ppm phenyl (phenyl), 6.0, 5.9ppm (Φ-OCH ₂ CH=CH ₂ and Φ-CH ₂ CH=CH ₂ ), 5.2, 5.4ppm (Φ-OCH ₂ CH=CH ₂ ), 4.95ppm (Φ-CH ₂ CH=CH ₂ ), 4.5ppm (Φ-OCH ₂ CH=CH ₂ ), 3.9, 3.8, 3.7ppm (Φ-CH ₂ -Φ), 3.3ppm (Φ-CH ₂ CH=CH ₂ ), 1.8ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si), 0.7 ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si).

²⁹ Si-NMR (using deuterated acetone containing TMS as solvent, TMS chemical shift at 0ppm as standard): 9.58ppm (Φ-CH ₂ CH ₂ CH ₂ -Si and Φ-OCH ₂ CH ₂ CH ₂ -Si ), -19.63 ppm and -20.18 ppm [(CH ₃ ) ₂ SiO].

Step 5: Add 85.00 g (0.55 mol of allyl groups) of the polysiloxane-containing allyl novolac resin obtained above into a 500 ml three-necked flask equipped with mechanical stirring, a spherical condenser and a thermometer, and bismaleyl 28.46g of imine monomer (0.16mol of maleimide group) and 280ml of 4-methyl-2-pentanone were heated to reflux for 1h, and then the solvent was removed by rotary evaporator to obtain polysiloxane-modified olefin Propyl novolac/BMI resin blend, its appearance is dark red transparent liquid.

Step 6: Pour the polysiloxane-modified allyl novolac resin/BMI blend obtained above into the mold, and carry out in a common oven according to the procedure of 160°C 4h+200°C 4h+250°C 6h Heat and solidify to obtain a resin cast body.

TGA analysis showed that the 5wt% weight loss temperature of the cured resin was 419.8°C, and the mass retention rate at 900°C was 32.43%. The impact test shows that the impact strength of the cast resin is 6.12kJ/m ² , which is 2.6 times that of the unmodified allyl phenolic/BMI resin.

Example 4

Step 1: Same as Step 1 in Example 1.

Step 2: Add 150.00 g (0.51 mol) of octamethylcyclotetrasiloxane (D ₄ ) and 9.25 g (0.069 mol) of tetramethyldisiloxane (M ^H M ^H ) into a 500 ml three-necked flask equipped with mechanical stirring ), fully stirred evenly; under vigorous stirring, 7.50 g of concentrated sulfuric acid was added dropwise, and reacted at 10°C for 6 hours; 2.84 g of deionized water was added, and the reaction was continued for 6 hours. After the reaction stopped, the reaction solution was transferred to a separatory funnel, the acid layer was separated, and then washed with a large amount of deionized water until pH = 7; finally, the low boiler was removed by vacuum distillation to obtain a hydrogen-terminated poly Dimethicone (2).

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 0.08ppm[(CH ₃ ) ₂ SiO], 0.19ppm[HSi(CH ₃ ) ₂ ], 4.71 ppm (SiH).

²⁹ Si-NMR (deuterated acetone containing TMS as solvent, TMS chemical shift at 0 ppm as standard): -5.47ppm (Si-H), -18.58ppm, -20.54ppm [(CH ₃ )SiO].

The number average molecular weight of the above-mentioned polydimethylsiloxane (2) was calculated as 3000 based on the integrated areas at 0.08 ppm and 0.19 ppm in ¹ H-NMR.

Step 3: Same as Step 3 in Example 1.

Step 4: add allyl novolac resin 100.00g (0.24mol) in a four-necked flask equipped with mechanical stirring, N _inlet , thermometer and spherical condenser, the hydrogen-terminated polysiloxane ( 2) 5.44g (0.0019mol), 3.26g (0.0043mol) of hydrogen-terminated polysiloxane (1) with a number average molecular weight of 750 and 150.00g of tetrahydrofuran, refluxed for 1h under the protection of nitrogen; then, lowered to 25°C, Add 1.20ml of xylene solution of H ₂ PtCl ₆ , wherein the content of Pt in the xylene solution is 5wt%, raise the temperature to 50°C, and react for 12h; The solvent was removed by an evaporator to obtain polysiloxane-modified allyl novolac resin containing 5 wt % of a number average molecular weight of 3000 and 3 wt % of a number average molecular weight of 750, and the appearance was wine red transparent liquid.

Using ¹ H-NMR, ²⁹ Si-NMR to characterize its structure:

¹ H-NMR (using TMS-free deuterated acetone as solvent, the chemical shift of acetone at 2.05ppm as standard): 7.1, 7.0, 6.9, 6.8ppm phenyl (phenyl), 6.0, 5.9ppm (Φ-OCH ₂ CH=CH ₂ and Φ-CH ₂ CH=CH ₂ ), 5.2, 5.4ppm (Φ-OCH ₂ CH=CH ₂ ), 4.95ppm (Φ-CH ₂ CH=CH ₂ ), 4.5ppm (Φ-OCH ₂ CH=CH ₂ ), 3.9, 3.8, 3.7ppm (Φ-CH ₂ -Φ), 3.3ppm (Φ-CH ₂ CH=CH ₂ ), 1.8ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si), 0.7 ppm (Φ-CH ₂ CH ₂ -CH ₂ -Si and Φ-O-CH ₂ CH ₂ -CH ₂ -Si).

²⁹ Si-NMR (using deuterated acetone containing TMS as solvent, TMS chemical shift at 0ppm as standard): 9.58ppm (Φ-CH ₂ CH ₂ CH ₂ -Si and Φ-OCH ₂ CH ₂ CH ₂ -Si ), -19.63 ppm and -20.18 ppm [(CH ₃ ) ₂ SiO].

Step 5: Add 85.00 g (allyl group 0.56 mol) of polysiloxane obtained above in a 500 ml three-necked flask equipped with mechanical stirring, a spherical condenser and a thermometer, bismaleimide Amine monomer 40.09g (maleimide group 0.22mol) and 4-methyl-2-pentanone 280ml, heated to reflux for 1h, and then use a rotary evaporator to remove the solvent to obtain polysiloxane-modified allyl Base novolac/resin BMI blend, its appearance is dark red transparent liquid resin.

Step 6: Pour the polysiloxane-modified allyl novolac resin/BMI blend obtained above into a mold, and carry out in a common oven according to the procedure of 160°C 4h+200°C 4h+250°C 6h Heat and solidify to obtain a resin cast body.

TGA analysis showed that the 5wt% weight loss temperature of the cured resin was 418.5°C, and the mass retention rate at 900°C was 34.14%. The impact test shows that the impact strength of the cast resin is 4.67kJ/m ² , which is 2.0 times that of the unmodified allyl phenolic/BMI resin.

Claims (8)

1. the allyl group linear phenolic aldehyde/bimaleimide resin of a polysiloxane toughening is characterized in that: can adopt following method preparation:

(1) end capped polydimethylsiloxane 1 of 1～5 weight part hydrogen and the end capped polydimethylsiloxane 2 of 5 weight part hydrogen are mixed with the solution that contains 90～94 weight part allyl group linear resol, in 50 ℃～80 ℃, under the metal catalyst effect of catalytic amount, react, obtain the allyl group linear resol of polysiloxane toughening;

(2) the bismaleimide amine monomers is joined in the product of step (1), wherein the mol ratio of maleimide base group and allyl group is 0.3～0.6: 1; In solvent, reflux, remove the allyl group linear phenolic aldehyde/bimaleimide resin that obtains polysiloxane toughening after desolvating;

The general formula of the end capped polydimethylsiloxane of described hydrogen is:

Wherein, the several 6≤p of repeating segment≤8 of the end capped polydimethylsiloxane 1 of hydrogen, number-average molecular weight is 500～800; Several 20≤the p of repeating segment≤40 of the end capped polydimethylsiloxane 2 of hydrogen, number-average molecular weight is 1500～3000.

2. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the structural formula of described allyl group linear resol is:

Wherein, m+n＞1, number-average molecular weight scope 550～900.

3. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the metal catalyst in the described step (1) is H ₂PtCl ₆Aqueous isopropanol or H ₂PtCl ₆Xylene solution.

4. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 3 is characterized in that: described H ₂PtCl ₆The volumetric molar concentration of aqueous isopropanol be 0.004～0.008M; Described H ₂PtCl ₆Xylene solution in the content of Pt be 3～5wt%.

5. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the solvent of the solution of the allyl group linear resol in the described step (1) is toluene, 4-methyl-2 pentanone or tetrahydrofuran (THF).

6. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the solvent in the described step (2) is 4-methyl-2 pentanone or butanone.

7. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the reaction times in the described step (1) is 4～12 hours.

8. the allyl group linear phenolic aldehyde/bimaleimide resin of polysiloxane toughening according to claim 1, it is characterized in that: the return time in the described step (2) is 1～2 hour.