CN111944311A

CN111944311A - Method for preparing nylon 66/polyphenyl ether plastic alloy

Info

Publication number: CN111944311A
Application number: CN202010894644.5A
Authority: CN
Inventors: 张振亚; 杨明成; 宋伟强; 吕峰和; 蔡坤鹏; 刘树博; 刘文涛; 张本尚; 王晓慧; 郭文慧; 田青亮; 陈阳; 王宏正; 梁运增
Original assignee: Jiaozuo Tongfu Technology Co Ltd; Suzhou Ficton Plastic Co Ltd; Isotope Institute Co ltd Of Henan Academy Of Sciences; Henan Academy of Sciences
Current assignee: Jiaozuo Tongfu Technology Co Ltd; Suzhou Ficton Plastic Co Ltd; Isotope Institute Co ltd Of Henan Academy Of Sciences; Henan Academy of Sciences
Priority date: 2020-08-31
Filing date: 2020-08-31
Publication date: 2020-11-17
Anticipated expiration: 2040-08-31
Also published as: CN111944311B

Abstract

The invention belongs to the field of high polymer materials, and discloses a method for preparing a nylon 66/polyphenyl ether plastic alloy. The method comprises the following steps: melting and mixing maleic anhydride and polystyrene together, and extruding and granulating; then placing the granules in a gamma ray radiation field for irradiation, and mixing the irradiated granules with nylon 66 and polyphenyl ether; and finally, extruding and granulating the mixture on an extruder to obtain the nylon 66/polyphenyl ether plastic alloy. The nylon 66/polyphenyl ether plastic alloy obtained by the preparation method improves the compatibility of materials and ensures that the obtained alloy has better mechanical property.

Description

Method for preparing nylon 66/polyphenyl ether plastic alloy

Technical Field

The invention relates to a plastic alloy, in particular to a method for preparing a nylon 66/polyphenyl ether alloy, belonging to the field of high polymer materials.

Background

Nylon 66, one of the engineering plastics, has many excellent properties, such as good dimensional stability, high strength, and the like, and is widely used in the fields of automobiles, machine manufacturing, electronic and electrical appliances, and the like. Polyphenylene oxide is also an engineering plastic and has the advantages of high rigidity, high heat resistance, flame retardancy, high strength, excellent electrical property and the like. In addition, the polyphenyl ether also has the advantages of wear resistance, no toxicity, pollution resistance and the like. The dielectric constant and dielectric loss of polyphenylene ether are one of the smallest varieties in engineering plastics, and are hardly affected by temperature and humidity. However, it has poor fluidity and is difficult to process. The nylon 66 and the polyphenyl ether are blended to prepare the alloy of the two engineering plastics, so that the advantages of the nylon 66 and the polyphenyl ether can be combined, the flame retardance is given to the nylon 66, and the flowability of the polyphenyl ether is improved. However, the compatibility between nylon 66 and polyphenyl ether is poor, the bonding capability at the interface is poor, and the mechanical property of the alloy is poor. There is a need to find better ways to improve the overall properties of the alloy.

Disclosure of Invention

In order to overcome the defects of poor compatibility of nylon 66 and polyphenyl ether and poor mechanical property of the alloy, the invention provides a novel improved method for preparing a nylon 66/polyphenyl ether plastic alloy.

The method comprises the following four steps:

firstly, melting and mixing Maleic Anhydride (MAH) and Polystyrene (PS), and extruding and granulating, wherein the weight ratio of the polystyrene to the maleic anhydride is 1: 0.05-0.5;

step two, placing the granules prepared in the step one in a gamma ray radiation field for irradiation treatment, wherein the absorbed dose is 1 kGy-100 kGy;

mixing the irradiated granules with nylon 66, polyphenyl ether and an auxiliary agent together, wherein the weight ratio of the nylon 66 to the polyphenyl ether to the granules to the auxiliary agent is 100: 10-100: 1-25: 1-20;

and step four, extruding and granulating the mixture on an extruder to obtain the nylon 66/polyphenyl ether plastic alloy.

The principle of the invention is as follows: in the second step, the irradiated material generates active sites such as free radicals under the action of gamma rays, and the active sites can initiate MAH polymerization. The active points are positioned on a PS molecular chain to form a polymaleic anhydride graft chain, and the graft is marked as PS-g-MAH; when the active sites are located on other components such as maleic anhydride, non-grafted polymaleic anhydride is formed. The PS-g-MAH has good compatibility with the polyphenyl ether, and the polymaleic anhydride grafted chain has good compatibility with the nylon 66, so that the PS-g-MAH can connect the nylon 66 and the polyphenyl ether at the interface, the compatibility of the nylon 66 and the polyphenyl ether is improved, and the mechanical property of the alloy is better.

Compared with the prior art, the technical advantages of the invention are mainly embodied in the following aspects:

there are many methods for preparing PS-g-MAH, which can be roughly classified into chemical method and radiation method. The so-called chemical method uses an initiator to form active sites on the PS macromolecule, on which MAH grows to form graft chains, but more so, the initiator directly initiates MAH polymerization to form a polymaleic anhydride homopolymer. In order to improve the graft chain of MAH, a solution grafting process, a semi-solution grafting process, and a reactive extrusion grafting process can be adopted. The solution and semi-solution grafting process needs to use an organic solvent and is not environment-friendly. The cylinder temperature of PS during processing is generally 180-250 ℃, the initiator selected during reactive extrusion grafting must be adapted to the cylinder temperature, a high-temperature initiator needs to be selected, otherwise, the half-life is short, and the MAH conversion rate is low.

The irradiation method is to form active sites by irradiation with ultraviolet light, high-energy rays, or the like. Ultraviolet irradiation grafting needs a photosensitizer, is still a chemical method in nature, and has low grafting rate. High energy radiation has different laws and does not require photosensitizers. Active points are forcibly formed in the system under the action of high-energy radiation, and MAH graft polymerization or homopolymerization is initiated by the active points. Among the high-energy radiation methods, gamma-ray radiation methods have promising industrial prospects. The gamma ray radiation grafting comprises two methods of co-radiation grafting and pre-radiation grafting. Co-irradiation grafting is to irradiate the polymer and the monomer together with gamma rays, and pre-irradiation grafting is to irradiate the polymer first and then mix the polymer and the monomer. The pre-irradiation grafting is characterized in that the homopolymer chains of MAH are few, and most of the MAH are graft chains, but the defects are obvious, namely most of monomers are not polymerized, and the conversion rate of MAH is low. Relatively speaking, the co-irradiation grafting can be completed in one step, and the operation is simple and easy. The realization of the co-radiation grafting can be in three forms, firstly, after the polymer and the monomer are uniformly mixed in the solution, the solvent is removed, and then the ray irradiation is carried out; secondly, simply mixing polymer powder and monomer powder together, and then performing ray irradiation; thirdly, the polymer and the monomer are melted and blended together, and then the radiation irradiation is carried out. Compared with the three forms, the first form has the disadvantages of using organic solvent and being not environment-friendly; the second form has a poor intimate contact between the polymer and the monomer and a low degree of grafting. The third form overcomes the disadvantages of the other two forms, and does not use organic solvents, and the polymer and monomer are in relatively close contact. The step two of the invention adopts a third form. The nylon 66/polyphenyl ether plastic alloy obtained by the preparation method improves the compatibility of materials and ensures that the obtained alloy has better mechanical property.

Detailed Description

To better illustrate the invention, the following examples are given:

example 1

400g of polystyrene and 100g of maleic anhydride were weighed and melt-blended in an internal mixer. Taking out the mixture, filling into a polyethylene bag, sealing, and irradiating in a gamma ray radiation field. The absorbed dose was 10kGy, dose rate 1 kGy/hour. Taking out and crushing to obtain the polystyrene grafted maleic anhydride (PS-g-MAH) powder.

10kg of nylon 66, 5.5kg of polyphenylene ether, 1.5kg of PS-g-MAH and 0.2kg of a nylon processing lubricant (brand CYD-PR 121) were weighed and blended together, respectively. And extruding and granulating by using a double-screw extruder to obtain the nylon 66/polyphenyl ether plastic alloy.

And (3) measuring the mechanical property: tensile strength of 77.4MPa, bending strength of 85.8MPa, bending modulus of 2.66GPa, impact strength (notch) of 12.5KJ/m²。

Example 2

600g of polystyrene and 200g of maleic anhydride were weighed and melt-blended in an internal mixer. Taking out the mixture, filling into a polyethylene bag, sealing, and irradiating in a gamma ray radiation field. The absorbed dose was 5kGy, dose rate 1 kGy/hour. Taking out and crushing to obtain the polystyrene grafted maleic anhydride (PS-g-MAH) powder.

7.5kg of nylon 66, 5kg of polyphenylene ether, 1.8kg of PS-g-MAH and 0.2kg of a nylon processing lubricant (brand CYD-PR 121) were weighed and blended together, respectively. And extruding and granulating by using a double-screw extruder to obtain the nylon 66/polyphenyl ether plastic alloy.

And (3) measuring the mechanical property: tensile strength of 81.3MPa, bending strength of 82.5MPa, bending modulus of 2.54GPa, impact strength (notch) of 8.26KJ/m²。

Comparative example 1

400g of polystyrene and 100g of maleic anhydride were weighed and dissolved in 400g of acetone and 100g of chloroform, respectively. Then, the two solutions were mixed together and mixed uniformly by ultrasonic oscillation. Petroleum ether was added to the mixed solution to effect precipitation. Removing the upper layer solution, placing the lower layer gel resin in a vacuum oven, vacuumizing at 50 ℃, and drying to constant weight. Taking out, pulverizing, placing into polyethylene bag, sealing, and irradiating in gamma ray radiation field. The absorbed dose was 10kGy, dose rate 1 kGy/hour. And irradiating to obtain the powdery polystyrene grafted maleic anhydride (PS-g-MAH).

And (3) measuring the mechanical property: tensile strength 54.3MPa, bending strength 78.4MPa, bending modulus 2.33GPa, impact strength (notch) 5.75KJ/m²。

Comparative example 2

Weighing 400g of polystyrene, and crushing; 100g of maleic anhydride was weighed out and dissolved homogeneously in 50g of acetone. Adding the polystyrene powder into acetone solution of maleic anhydride, and uniformly mixing. After 12 hours of standing, residual acetone was removed by vacuum at room temperature. Taking out, placing into polyethylene bag, sealing, and irradiating in gamma ray radiation field. The absorbed dose was 5kGy, dose rate 1 kGy/hour. Taking out and crushing to obtain the polystyrene grafted maleic anhydride (PS-g-MAH) powder.

And (3) measuring the mechanical property: tensile strength 58.7MPa, bending strength 72.2MPa, bending modulus 2.28GPa, impact strength (notch) 5.12KJ/m²。

It can be seen that the nylon 66/polyphenyl ether plastic alloy obtained by the preparation method of the invention improves the compatibility of materials and leads the mechanical property of the obtained alloy to be better by adopting the co-radiation grafting.

In addition, the weight ratio of the maleic anhydride and the polystyrene has an influence on the alloy performance, and the dosage of the PS-g-MAH also has an influence on the alloy performance, and the results are as follows:

TABLE 1 Effect of MAH and PS ratio in compatibilizer PS-g-MAH on PA/PPO alloy Properties

Serial number	I	II	III	IV	V	VI	VII	VIII
									PS/MAH ratio	1:0.05	1:0.1	1:0.25	1:0.5	1:0.05	1:0.1	1:0.25	1:0.5
Grafting method	Radiation of radiation	Radiation of radiation	Radiation of radiation	Radiation of radiation	Chemistry	Chemistry	Chemistry	Chemistry
									Tensile Strength (MPa)	63.1	68.3	77.4	70.4	59.6	64.5	68.9	66.2
Flexural Strength (MPa)	54.8	73.1	85.8	84.7	4.4	4.6	4.7	4.4
									Flexural modulus (GPa)	2.33	2.49	2.66	2.65	2.18	2.43	2.51	2.55
Impact Strength: (KJ/m)²）	6.7	10.8	12.5	11.3	5.6	8.2	9.4	9.7

The alloy component ratio is PA/PPO/PS-g-MAH/lubricant 100/55/15/2

Notched izod impact strength

TABLE 2 influence of the amount of compatibilizer PS-g-MAH used in PA/PPO alloys on the properties of the alloys

Serial number	IX	X	XI	XII	XIII
						PA/PPO/PS-g-MAH	100/55/0	100/55/5	100/55/10	100/55/15	100/55/20
Tensile Strength (MPa)	49.2	68.4	75.2	77.4	78.5
						Flexural Strength (MPa)	65.8	78.2	83.6	85.8	86.8
Flexural modulus (GPa)	2.11	2.39	2.61	2.66	2.71
						Impact Strength: (KJ/m)²）	2.73	5.28	8.68	12.5	13.9

The PS/MAH ratio in the compatibilizer is 1:0.25

Notched izod impact strength

Claims

1. A method for preparing nylon 66/polyphenyl ether plastic alloy is characterized in that: the method is realized by the following steps:

(1) melting and mixing maleic anhydride and polystyrene together, and extruding and granulating, wherein the weight ratio of the polystyrene to the maleic anhydride is 1: 0.05-0.5;

(2) placing the granules prepared in the step (1) in a gamma ray radiation field for irradiation treatment;

(3) mixing the irradiated granules with nylon 66, polyphenyl ether and an auxiliary agent together, wherein the weight ratio of the nylon 66 to the polyphenyl ether to the granules to the auxiliary agent is 100: 10-100: 1-25: 1-20;

(4) extruding and granulating the mixture on an extruder to obtain nylon 66/polyphenyl ether plastic alloy;

the auxiliary agent is one or more of a flame retardant, an anti-aging agent and a lubricant.

2. The method for preparing a nylon 66/polyphenylene ether plastic alloy according to claim 1, wherein the absorbed dose of irradiation in the step (2) is 1kGy to 100 kGy.