Hyperbranched polysiloxane flexibilizer, preparation method thereof and application of hyperbranched polysiloxane flexibilizer in preparation of epoxy resin matrix of glass fiber reinforced plastic pipeline

Abstract

The invention belongs to the technical field of epoxy resin, and particularly relates to a hyperbranched polysiloxane flexibilizer, a preparation method thereof and application of the hyperbranched polysiloxane flexibilizer in preparation of an epoxy resin matrix of a glass fiber reinforced plastic pipeline. The preparation method comprises the following steps: carrying out addition reaction on hydroxyl-terminated polyether modified silicone oil and toluene diisocynate to prepare an intermediate, and then reacting with a chain extender diethanol amine to obtain the hyperbranched polysiloxane toughening agent containing amino groups. The flexibilizer provided by the invention is of a hyperbranched three-dimensional structure, molecules have Si-O-Si flexible chain segments, and molecular chains contain amino groups, so that the flexibilizer has excellent compatibility with epoxy resin, can effectively improve the brittleness of an epoxy resin cross-linked network and improve the impact resistance of the resin, and has small influence on the tensile strength and heat resistance of the resin. The epoxy resin containing the toughening agent can be used for manufacturing the glass fiber reinforced plastic pipeline for an oil field, and the toughness of the existing glass fiber reinforced plastic pipeline is effectively improved.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy resins, and specifically relates to a hyperbranched polysiloxane toughening agent and a preparation method thereof, and application thereof in preparing an epoxy resin matrix for a glass fiber reinforced plastic pipeline. Background Art

[0002] Epoxy FRP pipe is a composite material pipe made of continuous glass fiber as reinforcement material and epoxy resin as matrix through winding and curing. Due to the characteristics of high pressure bearing (up to 30MPa), corrosion resistance, light weight, not easy to scale, and easy to form, epoxy FRP pipe has been widely used in the ground gathering and transportation system of domestic oil fields, mainly used in the fields of oil and gas mixed transportation, water injection and water transportation, oil gathering and transportation, gas gathering and transportation. High-pressure FRP pipes for oil fields generally use bisphenol A epoxy resin (E54) as the matrix material and methyltetrahydrophthalic anhydride as the curing agent, and are prepared by high-temperature heating and curing. The product of this epoxy resin after curing is relatively brittle and has poor impact resistance. Therefore, when FRP pipes are used in oil fields, they are prone to cracking when encountering external mechanical shocks, terrain undulations and settlements, and leakage incidents caused by this often occur. In order to ensure the safe service of epoxy FRP pipes, it is necessary to improve the toughness of the epoxy resin matrix used in pipes and enhance its impact resistance.

[0003] At present, the commonly used methods for toughening epoxy resins include: toughening with rubber elastomers, toughening with rigid nanoparticles, toughening with block copolymers, and toughening with thermoplastics. The mechanical strength and heat resistance of epoxy resins will be significantly reduced after toughening with rubber elastomers, toughening with rigid nanoparticles is prone to agglomeration, which affects the toughening effect, toughening with block copolymers will introduce impurities, and toughening with thermoplastics will increase the viscosity of the resin and reduce the processing performance. Therefore, it is necessary to find a resin matrix toughening agent suitable for epoxy fiberglass pipes, which will not significantly reduce the mechanical strength and heat resistance (glass transition temperature Tg) of the resin while improving the toughness of the epoxy resin, and the viscosity of the toughened resin is moderate, and has good processing performance.

[0004] Hyperbranched polysiloxane (HBPSi) molecules are highly branched, and the molecular chain is flexible and has a three-dimensional structure, which can effectively absorb and disperse external impact energy and improve the impact toughness of epoxy resin. In addition, its molecular chain segments are less entangled, low in viscosity, good in compatibility with epoxy resin, and good in thermal stability, which is conducive to improving the mechanical strength and heat resistance of epoxy resin, and has a good comprehensive toughening effect. Summary of the invention

[0005] In order to solve the deficiencies of the prior art, the present invention provides a hyperbranched polysiloxane toughening agent and a preparation method thereof and an application thereof in preparing an epoxy resin matrix of a glass fiber reinforced plastic pipe. The present invention provides a hyperbranched polysiloxane toughening agent containing amino groups, which can be added to epoxy resin to improve the impact resistance of the epoxy resin, and has little effect on tensile strength and heat resistance, thereby achieving effective toughening of the epoxy resin.

[0006] The technical solution provided by the present invention is as follows:

[0007] A method for preparing a hyperbranched polysiloxane toughening agent comprises the following steps:

[0008] 1) Mixing the two raw materials of terminal hydroxyl polyether modified silicone oil and toluene diisocyanate uniformly and heating them for reaction;

[0009] 2) After the partial reaction in step 1), a catalyst dibutyltin dilaurate is added to the reactants to continue the reaction, and finally a chain extender diolamine is added to the reactants to catalyze the reaction. After the reaction is completed, the temperature is cooled to room temperature to obtain a light yellow liquid product, which is a hyperbranched polysiloxane toughening agent (HBPSi) containing amino groups. The diolamine is diethanolamine, dipropanolamine or dibutanolamine, preferably diethanolamine;

[0010] Among them, the structural formula of the hydroxyl-terminated polyether modified silicone oil is as follows:

[0011]

[0012] The hydroxyl-terminated polyether modified silicone oil can be selected from the prior art, such as the SF-8427 product of Dow Corning Company, which has a molecular weight of 2000 g / mol.

[0013] The principle of the above preparation method is as follows:

[0014]

[0015] The above technical solution adopts the addition reaction of terminal hydroxyl polyether modified silicone oil and toluene diisocyanate to prepare an intermediate, and then reacts with the chain extender diethanolamine to obtain a hyperbranched polysiloxane toughening agent containing amino groups.

[0016] The obtained toughening agent has a hyperbranched three-dimensional structure, has a Si-O-Si flexible chain segment in the molecule, and contains amino groups in the molecular chain. It has excellent compatibility with epoxy resin, can effectively improve the brittleness of the epoxy resin cross-linking network, and enhance the impact resistance of the resin, while having little effect on the tensile strength and heat resistance of the resin.

[0017] Specifically, the preparation method of the hyperbranched polysiloxane toughening agent includes the following steps: adding two raw materials, terminal hydroxyl polyether modified silicone oil and toluene diisocyanate, into a container, and the molar ratio of terminal hydroxyl polyether modified silicone oil to TDI is 1: (1.8-2.2). After the reactants are evenly mixed, heating is started, the reaction temperature is controlled at 65-95°C, and the reaction time is 40-90min. Then, the catalyst dibutyltin dilaurate is added to the reactants, the molar ratio of terminal hydroxyl polyether modified silicone oil to DBTDL is 1: (0.0008-0.003), and the catalytic reaction continues for 40-80min. Finally, the chain extender diethanolamine is added to the reactants, the molar ratio of terminal hydroxyl polyether modified silicone oil to DEA is 1: (1-2), and the catalytic reaction is carried out for 40-80min. After the reaction is completed, the temperature is cooled to room temperature, and a light yellow liquid product can be obtained, which is a hyperbranched polysiloxane containing amino groups (HBPSi).

[0018] Specifically, the reaction temperature of step 2) is the same as the reaction temperature of step 1).

[0019] The two-step reaction can adopt the same temperature, which can simplify the preparation process.

[0020] The present invention also provides a hyperbranched polysiloxane toughening agent prepared according to the above method. The hyperbranched polysiloxane toughening agent has the following structure:

[0021]

[0022] The invention also provides the application of the hyperbranched polysiloxane toughening agent for preparing the epoxy resin matrix of the glass fiber reinforced plastic pipeline.

[0023] The hyperbranched polysiloxane toughening agent provided by the present invention has excellent compatibility with epoxy resin, can effectively improve the brittleness of the epoxy resin cross-linked network, improve the impact resistance of the resin, and has little effect on the tensile strength and heat resistance of the resin. The epoxy resin toughened with the hyperbranched polysiloxane toughening agent can be used in the manufacture of glass fiber reinforced plastic pipes for oil fields, effectively improving the toughness of existing glass fiber reinforced plastic pipes.

[0024] The preparation method of the epoxy resin matrix of the glass fiber reinforced plastic pipe is specific, comprising the following steps: adding the hyperbranched polysiloxane toughening agent to the E54 epoxy resin and mixing evenly, then adding the curing agent methyltetrahydrophthalic anhydride and the curing accelerator benzyltriethylammonium chloride, reacting and curing, and obtaining the glass fiber reinforced plastic pipe epoxy resin matrix.

[0025] Specifically, the amount of the hyperbranched polysiloxane toughening agent added is 4% to 11% of the mass of the epoxy resin;

[0026] Specifically, the mass ratio of epoxy resin, curing agent and accelerator is 1:(0.7-0.9):(0.01-0.03).

[0027] Specifically, the curing is performed at 70-90°C for 9-10 minutes, at 120-140°C for 14-146 minutes, and at 160-190°C for 28-32 minutes.

[0028] Beneficial effects:

[0029] The invention provides a method for preparing a hyperbranched polysiloxane toughening agent for an epoxy resin matrix of a glass fiber reinforced plastic pipeline, wherein an intermediate is prepared by an addition reaction of a terminal hydroxyl polyether modified silicone oil and toluene diisocyanate, and then the intermediate is reacted with a chain extender diethanolamine to obtain a hyperbranched polysiloxane toughening agent containing an amino group. The toughening agent provided by the invention is a hyperbranched three-dimensional structure, has a Si-O-Si flexible segment in the molecule, and contains an amino group in the molecular chain, has excellent compatibility with epoxy resin, can effectively improve the brittleness of the epoxy resin cross-linking network, improve the impact resistance of the resin, and has little effect on the tensile strength and heat resistance of the resin. The epoxy resin containing the toughening agent can be used for the manufacture of glass fiber reinforced plastic pipelines for oil fields, and effectively improves the toughness of existing glass fiber reinforced plastic pipelines. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is the infrared spectrum of the hyperbranched polysiloxane toughening agent prepared in Example 1.

[0031] Figure 2 This is a scanning electron microscope image of the cross section of the sample of the hyperbranched polysiloxane toughened epoxy resin cured material prepared in Example 1 after impact damage.

[0032] Figure 3 This is a scanning electron microscope image of the cross section of the sample after impact damage of the original resin system. DETAILED DESCRIPTION

[0033] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0034] Example 1

[0035] (1) 200 g (0.1 mol) of terminal hydroxyl polyether modified silicone oil (molecular weight 2000 g / mol) and 34.83 g (0.2 mol) of toluene diisocyanate were added to a 500 mL three-necked flask, the raw materials were mixed evenly with a stirring paddle, the temperature was raised to 80°C, and the reaction was carried out at this temperature for 60 min. Subsequently, 0.11 g (0.0002 mol) of catalyst dibutyltin dilaurate was added to continue the catalytic reaction for 60 min, and finally 15.77 g (0.15 mol) of chain extender diethanolamine was added to catalytic reaction for 60 min. After the reaction was completed, the temperature was cooled to room temperature to obtain a hyperbranched polysiloxane containing amino groups. The molecular weight was about 7200 g / mol.

[0036] (2) Take 100g of E54 epoxy resin, add 8g of the prepared hyperbranched polysiloxane to the resin and stir evenly. There is no obvious change in the viscosity of the resin during stirring. Then add 80g of methyltetrahydrophthalic anhydride as a curing agent and 2g of benzyltriethylammonium chloride as a curing accelerator. Pour the mixed resin mixture into a polytetrafluoroethylene mold for preparing impact bars and tensile bars, and cure at 80°C for 10min, 130°C for 15min, and 170°C for 30min. The prepared bars are tested for impact strength, tensile strength, and glass transition temperature.

[0037] Example 2

[0038] (1) 300 g (0.05 mol) of hydroxyl-terminated polyether modified silicone oil (molecular weight 6000 g / mol) and 18.29 g (0.105 mol) of toluene diisocyanate were added to a 500 mL three-necked flask, the raw materials were mixed evenly with a stirring paddle, the temperature was raised to 90°C, and the reaction was carried out at this temperature for 40 min. Subsequently, 0.08 g (0.0001 mol) of catalyst dibutyltin dilaurate was added to continue the catalytic reaction for 40 min. Finally, 9.46 g (0.09 mol) of chain extender diethanolamine was added and the catalytic reaction was carried out for 50 min. After the reaction was completed, the temperature was cooled to room temperature to obtain a yellow liquid. The molecular weight was about 6500 g / mol.

[0039] (2) Take 100g of E54 epoxy resin, add 6g of the prepared hyperbranched polysiloxane to the resin and stir evenly. There is no obvious change in the viscosity of the resin during stirring. Then add 75g of methyltetrahydrophthalic anhydride as curing agent and 2.5g of benzyltriethylammonium chloride as curing accelerator. Pour the mixed resin mixture into the polytetrafluoroethylene mold for preparing impact specimens and tensile specimens, and cure at 75°C for 10min, 140°C for 15min, and 180°C for 30min. Perform corresponding tests on the prepared specimens.

[0040] Hyperbranched polysiloxane contains amino functional groups, which can improve compatibility with epoxy resin. The Si-O-Si flexible segment in the molecular structure and the cavity formed by the hyperbranched three-dimensional structure can effectively toughen epoxy resin, improve the impact strength of resin, and have less influence on the tensile strength and heat resistance (glass transition temperature Tg) of resin. After the above specific embodiments, the epoxy resin toughened by hyperbranched polysiloxane is obtained, and the test data of its impact strength, tensile strength and glass transition temperature are as shown in Table 1. It can be seen that the impact strength of the toughened epoxy resin in Example 1 and Example 2 increased by 61.59% and 49.84% relative to the original resin, the tensile strength only decreased by 4.9% and 6.15%, and the glass transition temperature remained basically unchanged.

[0041] Table 1 Test data of impact strength, tensile strength and glass transition temperature of toughened epoxy resin

[0042] Test items Original resin system Example 1 Toughened resin Example 2 Toughened resin <![CDATA[Impact strength (KJ / m 2 )]]> 9.71 15.69 14.55 Tensile strength(MPa) 67.52 64.21 63.37 Glass transition temperature(℃) 120.32 119.27 120.14

[0043] It can be seen from the above table that the appropriate addition of hyperbranched polysiloxane toughening agent can significantly improve the impact strength and toughness of epoxy resin without substantially affecting the tensile strength and glass transition temperature.

[0044] like Figure 1 As shown in the infrared spectrum of the hyperbranched polysiloxane toughening agent prepared in Example 1, it can be seen that 800 cm -1 and 1017cm -1 The peak at 1100 cm is the stretching vibration peak of Si-O-Si bond in hyperbranched polysiloxane. -1 The stretching vibration peak of COC is 1475 cm -1 , 1530cm-1 and 1600cm -1 The peak at 3350cm is the stretching vibration peak of the benzene ring. -1 The peak at the center is the stretching vibration peak of -OH, which proves that the raw materials have reacted to produce hyperbranched polysiloxane.

[0045] like Figure 2 As shown, from the scanning electron microscope image of the cross section of the sample after impact damage of the hyperbranched polysiloxane toughened epoxy resin cured material, it can be clearly seen that the cross section surface is rough, and it is a ductile fracture morphology, which is caused by the hyperbranched polysiloxane toughening the epoxy resin.

[0046] like Figure 3 As shown in the scanning electron microscope image of the cross section of the sample after impact damage of the original resin system, the cross section surface is flat, which is the morphology of brittle fracture. The reason is that the original resin system is relatively brittle.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a hyperbranched polysiloxane toughening agent, characterized in that: The following steps are involved: 1) Mixing the two raw materials of terminal hydroxyl polyether modified silicone oil and toluene diisocyanate uniformly and heating them for reaction; 2) After the partial reaction in step 1), a catalyst dibutyltin dilaurate is added to the reactants to continue the reaction, and finally a chain extender diolamine is added to the reactants to catalyze the reaction. After the reaction is completed, the temperature is cooled to room temperature to obtain a light yellow liquid product, which is a hyperbranched polysiloxane toughening agent containing amino groups; Among them, the structural formula of the hydroxyl-terminated polyether modified silicone oil is as follows:

2. The method for preparing a hyperbranched polysiloxane toughening agent according to claim 1, wherein In step 1): The two raw materials of terminal hydroxyl polyether modified silicone oil and toluene diisocyanate are mixed in a molar ratio of 1: (1.8-2.2); The reaction temperature is controlled at 65-95°C; Reaction time: 40 to 90 minutes.

3. The method for preparing a hyperbranched polysiloxane toughening agent according to claim 1, wherein In step 2), the molar ratio of the terminal hydroxyl polyether modified silicone oil to the catalyst is 1:(0.0008-0.003).

4. The method for preparing a hyperbranched polysiloxane toughening agent according to claim 1, wherein In step 2): The molar ratio of the terminal hydroxyl polyether modified silicone oil to diethanolamine is 1:(1-2); The diolamine is diethanolamine, dipropanolamine or dibutanolamine; Each reaction temperature is controlled at 65-95°C; Each reaction time is 40 to 80 minutes.

5. The method for preparing a hyperbranched polysiloxane toughening agent according to any one of claims 1 to 4, characterized in that: The reaction temperature of step 2) is the same as the reaction temperature of step 1).

6. A hyperbranched polysiloxane toughening agent prepared according to the preparation method according to any one of claims 1 to 5.

7. An application of the hyperbranched polysiloxane toughening agent according to claim 6, characterized in that: Used to prepare epoxy resin matrix for FRP pipes.

8. The use according to claim 7, characterized in that: The following steps are involved: The hyperbranched polysiloxane toughening agent is added to the E54 epoxy resin and mixed evenly, and then a curing agent methyltetrahydrophthalic anhydride and a curing accelerator benzyltriethylammonium chloride are added to react and cure to obtain the epoxy resin matrix of the glass fiber reinforced plastic pipe.

9. The use according to claim 8, characterized in that: The added amount of the hyperbranched polysiloxane toughening agent is 4% to 11% of the epoxy resin mass; The mass ratio of epoxy resin, curing agent and accelerator is 1:(0.7-0.9):(0.01-0.03).

10. The use according to claim 8 or 9, characterized in that: The reaction curing includes the following stages: curing at 70-90°C for 9-10 minutes, curing at 120-140°C for 14-146 minutes, and curing at 160-190°C for 28-32 minutes.

Images