1. The preparation method of the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material is characterized in that a compound A, polypropylene powder, an initiator and an auxiliary agent are mixed and then extruded through an extruder, wherein the compound A is formed by reacting benzyl or substituted benzyl with carboxyl of beta-naphthylacetic acid, and the benzyl of the compound A has a carbon-carbon double bond which can be grafted with polypropylene.

2. The method for preparing the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material according to claim 1, wherein the structural formula of the compound A is as follows:

in the structural formula, R represents H or an alkyl long chain of C1-C4 or an alkyl substituted chain of C1-C4.

3. The method for preparing the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material according to claim 2, wherein the components comprise, by mass: 75-85% of polypropylene powder, 3-7% of compound A, 0.05-0.5% of initiator and the balance of auxiliary agent.

4. The method for preparing the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material according to claim 3, wherein the auxiliary agent does not include an ultraviolet resistant component.

Background

Polypropylene (PP) is a general plastic, is developed rapidly in recent years, becomes a variety with the fastest yield increase in plastics, has the advantages of excellent processing performance, no toxicity, no smell, good luster and the like, and is widely used in the industries of transportation, buildings, household appliances and the like.

Currently, polypropylene modification is still mainstream in the exploration direction of polypropylene grafting organic acid so as to improve the physical properties of polypropylene finished products, such as strength, hydrophilicity, dyeability and the like.

The method for improving the grafting rate of polypropylene suspension graft acrylic acid is disclosed as application No. 201310594786.X, and comprises the steps of firstly carrying out step pretreatment on PP to reduce the crystallinity of the PP, simultaneously forming a large number of nano-scale micropores on graft particles, and then carrying out grafting reaction with an olefin monomer in a water suspension system.

The preparation method of the maleic acid grafted polypropylene with the application number of 201210413278.2 aims at shortening the reaction time, optimizing the grafting process and improving the grafting efficiency.

A maleic anhydride grafted polypropylene material with application number 201210461666.8, which is obtained by grafting reaction of maleic anhydride, propylene and grafting-assisting monomer under the action of an initiator and an antioxidant; the grafting-assisting monomer can play a role in improving the grafting rate and inhibiting the degradation of the cyclopropene, thereby effectively improving the grafting rate. Meanwhile, a new initiator is introduced to reduce the pungent odor of the maleic anhydride grafted polypropylene material, and the grafting reaction degree and the co-processing degree with the auxiliary monomer are improved, so that the prepared product has high grafting rate and low pungent odor.

The polypropylene graft having high melt strength of application No. 201410398666.7, which is prepared by compounding styrene-grafted polypropylene of two different melt flow rates of styrene-grafted polypropylene A and styrene-grafted polypropylene B and styrene-grafted polypropylene of different styrene graft ratios to obtain propylene graft, not only broadens the molecular weight distribution of propylene while simultaneously incorporating a long chain branching structure into the propylene graft, but also effectively boosts the melt strength of the propylene graft to obtain a polypropylene graft having high melt strength.

The preparation method of the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material with the application number of 201010185191.5 is characterized in that beta-naphthylacetic acid bonded polyacrylic acid is introduced and grafted with polypropylene to be used as a raw material for manufacturing an ecological environment-friendly bag, so that the composite material has the characteristics of good ultraviolet resistance, water absorption and water retention, is beneficial to plant growth, and has high strength, long service life and the like.

The inventor of the present invention has made extensive studies based on the patent application No. 201010185191.5, and found that the method does have a certain technical contribution to the field of plant bag subdivision, but has the following technical problems: the bonded beta-naphthylacetic acid is one of the components of the polypropylene composite material, and the beta-naphthylacetic acid does not have strong freeness, so that the beta-naphthylacetic acid has little effect of promoting the growth of plants.

Disclosure of Invention

The invention provides a preparation method of a chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material aiming at the problems in the prior art.

The invention solves the technical problems through the following technical means:

a preparation method of chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material comprises the steps of mixing a compound A, polypropylene powder, an initiator and an auxiliary agent, and extruding the mixture through an extruder, wherein the compound A is formed by reacting benzyl or substituted benzyl with carboxyl of beta-naphthylacetic acid, and the benzyl of the compound A has a carbon-carbon double bond which can be grafted with polypropylene.

Further, the structural formula of compound a is as follows:

in the structural formula, R represents H or an alkyl long chain of C1-C4 or an alkyl substituted chain of C1-C4.

Specifically, the compound A is one of the following structural formulas A1-A6:

further, each component comprises the following components in percentage by mass: 75-85% of polypropylene powder, 3-7% of compound A, 0.05-0.5% of initiator and the balance of auxiliary agent.

Furthermore, the auxiliary agent does not comprise an ultraviolet resistant component.

The invention has the beneficial effects that: according to the invention, the compound A is screened and designed before the grafting reaction, so that the compound A has the following characteristics: (1) has a reactive functional group capable of grafting with polypropylene; the compound A contains a complete beta-naphthylacetic acid structure, can release the beta-naphthylacetic acid under specific conditions, and has good stability. Based on the compound A, the compound A can be grafted to a polypropylene long chain through a grafting reaction, so that a polypropylene compound has an active structure of beta-naphthylacetic acid, plant bags prepared based on the propylene compound can be sprayed with trifluoroacetic acid, debenzylation is carried out at room temperature, free beta-naphthylacetic acid is released, and the beta-naphthylacetic acid has a biological growth regulation effect and can help plant growth regulation.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The preparation method of the chemically grafted polyacrylic acid bonded beta-naphthylacetic acid modified polypropylene composite material comprises the following components: compound A, polypropylene powder, initiator and assistant.

Polypropylene powder was purchased from Shandong Changyao New Material Co., Ltd, model CY-148572.

The initiator is one or more of azobisisobutyronitrile, azobisisobutylamidine dihydrochloride, potassium persulfate, dibenzoyl peroxide, potassium permanganate or ceric amine nitrate, and azobisisobutyronitrile (available from Nanjing Runfeng petrochemical Co., Ltd., CAS78-67-1) is used in the following examples.

The auxiliary agent comprises: antioxidant (BASF 168, 1010), and lubricant (silicone powder MB-4).

The structural formula of compound a is as follows:

in the structural formula, R represents H or an alkyl long chain of C1-C4 or an alkyl substituted chain of C1-C4.

Compound A is prepared by benzyl on beta-naphthylacetic acid and compound B, wherein compound B comprises 4-methylstyrene (hazardous material, not used in the examples below), 6-methyl-1H-indene (purchased from Shanghai Bide medical science and technology Co., Ltd., No. BD01007463), and 4- (p-tolyl) -3-buten-2-one (purchased from Shenzhen AiTuo chemical Co., Ltd., No. BD 90730).

The preparation method of the compound A comprises the following steps: adding beta-naphthylacetic acid into a mixed solution of potassium carbonate and dichloromethane, then slowly adding 4- (p-tolyl) -3-buten-2-one, heating to 30-40 ℃, wherein the mass ratio of the beta-naphthylacetic acid to the 4- (p-tolyl) -3-buten-2-one is (1.5-2): 1.

example 1

Preparing materials: 80g of polypropylene powder with the molecular weight of 6000, 7g of compound A, 0.2g of azobisisobutyronitrile, 5.3g of antioxidant and 7.5g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Example 2

Preparing materials: 85g of polypropylene powder with the molecular weight of 6000, 5g of compound A, 0.2g of azobisisobutyronitrile, 5.3g of antioxidant and 4.8g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Example 3

Preparing materials: 82g of polypropylene powder with the molecular weight of 6000, 5g of compound A, 0.2g of azobisisobutyronitrile, 5.3g of antioxidant and 7.8g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Example 4

Preparing materials: 82g of polypropylene powder with the molecular weight of 6000, 7g of compound A, 0.2g of azobisisobutyronitrile, 4.8g of antioxidant and 6g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Example 5

Preparing materials: 75g of polypropylene powder with the molecular weight of 6000, 7g of compound A, 0.5g of azobisisobutyronitrile, 10g of antioxidant and 7.5g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Example 5

Preparing materials: 85g of polypropylene powder with the molecular weight of 6000, 3g of compound A, 0.1g of azobisisobutyronitrile, 5.9g of antioxidant and 6g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Comparative example 1

Preparing materials: 80g of polypropylene powder with the molecular weight of 6000, 7g of polyacrylic acid with the molecular weight of 3000, 0.2g of azodiisobutyronitrile, 0.5g of beta-naphthylacetic acid, 7g of antioxidant and 5.3g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

Comparative example 2

Preparing materials: 70g of polypropylene powder with the molecular weight of 6000, 10g of polyacrylic acid with the molecular weight of 3000, 0.5g of azodiisobutyronitrile, 0.5g of beta-naphthylacetic acid, 10g of antioxidant and 9g of lubricant.

Preparing a polypropylene composite material: mixing the above raw materials in a mixer, and extruding into final product in a twin-screw extruder with rotation speed of 20rpm and temperature of 230 deg.C.

The free acid release amount of the finished products prepared in the above examples 1 to 6 and comparative examples 1 and 2 was measured.

The method comprises the following steps: preparing a finished product to be detected into a 20cm x 20cm square piece, placing at room temperature, spraying trifluoroacetic acid, standing for 6h, then spraying aniline to remove redundant trifluoroacetic acid, collecting liquid, extracting with methanol, concentrating, detecting with high performance liquid chromatography, and quantifying by an external standard method.

Reagents (analytically pure except for special instructions):

1) methanol: carrying out chromatographic purification;

2) glacial acetic acid;

3) a standard of beta-naphthylacetic acid;

4) 0.8% glacial acetic acid solution: accurately weighing 0.8mL of glacial acetic acid, adding water and fixing the volume to 100 mL;

5)0.1mg/mL β -naphthylacetic acid standard solution: accurately weighing 0.010g of beta-naphthylacetic acid;

the standard was dissolved with the mobile phase in a 100mL volumetric flask and the volume was brought to the mark.

The instrument comprises the following steps:

high performance liquid chromatograph: preparing an ultraviolet detector;

analytical balance: one dosage is 0.0001 g;

an ultrasonic cleaner;

volumetric flask: 25mL, 100 mL;

microporous filter membrane: 0.45 um.

The determination step comprises:

1) sample preparation: accurately weighing 0.10g of sample, placing in a 25mL volumetric flask, adding about 20mL of methanol, performing ultrasonic treatment in an ultrasonic water bath for 20min, fixing the volume to a scale with the methanol, placing for 4h, and filtering with a 0.45um filter membrane for later use;

2) and (3) standard product treatment: filtering the prepared standard solution through a 0.45um filter membrane, and taking the filtrate obtained after filtering as a control solution;

3) and (3) determination:

a chromatographic column: a C18 column, 150mm24.6mm 5/m, or equivalent;

mobile phase: methanol: 0.89% glacial acetic acid solution ═ 5a 50;

an ultraviolet detector: the wavelength is 221 mm;

column temperature: 30 ℃;

flow rate: 1.0 mL/min;

sample introduction volume: 20 mu L of the solution;

4) and (3) chromatographic analysis:

respectively injecting 20 mu L of beta-naphthylacetic acid standard solution and sample solution, performing liquid chromatography determination according to the listed conditions, recording peak areas, wherein response values are within a linear range detected by an instrument;

and (4) according to the retention time of the standard substance, determining the quality and quantifying by an external standard method.

5) And (3) calculating:

the formula:

in the formula: r is the residual amount (mg/L) of beta-naphthylacetic acid in a tested sample; ai-area of peak of beta-naphthylacetic acid in sample solution; ws-the mass of beta-naphthylacetic acid in the standard solution (ng); vf — sample final volumetric volume (mL); as is-the peak area of beta-naphthylacetic acid in the standard sample solution; vi — sample injection volume (uL); w-sample weight (g).

The test results are as follows:

according to the detection result, the plant cap bag can be used as a production raw material of the plant cap bag, trifluoroacetic acid can be sprayed according to requirements to release free beta-naphthylacetic acid, so that the growth of plants in the cap bag can be regulated, and the method can obviously improve the free release amount of the beta-naphthylacetic acid.

It is noted that, in this document, relational terms such as first and second, and the like, if any, are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.