CN103897106B - Method for improving grafting rate of polyolefin grafted unsaturated carboxylic acid monomer - Google Patents

Abstract

The invention provides a method for increasing the grafting ratio of polyolefin grafted unsaturated carboxylic acid monomers. The unsaturated carboxylic acid monomer is prepared by the reaction of acryloyl chloride or methacryloyl chloride and the corresponding amino acid under alkaline conditions; the unsaturated carboxylic acid monomer and cerium trichloride or its hydrate are simultaneously dissolved in N, N di Methylformamide or water to obtain solution A; dibenzoyl peroxide was dissolved in xylene to obtain solution B; polyolefin particles and styrene were placed in a water reaction vessel; solution A and solution B were added to the reaction In the container, stir at 60°C under nitrogen atmosphere for 1.5h, react at 95°C for 2 hours, then cool, wash, filter and dry. In the present invention, cerium trichloride and its hydrate are added to the reaction system. Due to the unique valence electron layer structure of the rare earth element cerium, the monomer can be activated through the coordination with the carbonyl group in the unsaturated carboxylic acid monomer structure. , thus improving its grafting reactivity, thereby increasing the grafting rate of the grafted product.

Description

Method for Improving Grafting Ratio of Polyolefin Grafted Unsaturated Carboxylic Acid Monomer

technical field

The invention relates to a method for grafting and modifying polyolefin, in particular to a method for improving the grafting rate of unsaturated carboxylic acid functionalized polyolefin prepared by the aqueous phase suspension solid phase grafting method.

Background technique

Polyolefin, represented by polypropylene (PP) and polyethylene (PE), is a general-purpose plastic with a wide range of uses. It has the advantages of large output, low price, water resistance, chemical resistance, and good molding process. It has become an influential Large and versatile commercial stock. With the continuous advancement of catalytic technology, polyolefin materials with controllable molecular structure and high performance have been synthesized, which are widely used in industries such as daily necessities, packaging, automobiles, construction and household appliances.

However, due to the inherent non-polarity and crystallinity of polyolefin materials, when they are blended with other materials such as polar polymers, inorganic fillers and metals, the interfacial force is poor. tension, increasing interfacial bonding. At the same time, their dyeability, adhesiveness, antistatic property, and hydrophilicity are also poor, which limits the application fields of polyolefin materials and restricts the further development of polyolefin materials. Functional modification of polyolefins through structural design can improve the compatibility and adhesion between such materials and other materials, thereby broadening the application range of polyolefin materials, and according to special requirements, design suitable for industry needs s material. At present, the technology of functionalized polyolefin based on graft modification has achieved satisfactory results, and the chemical graft modification of polyolefin has become a technical way to produce high value-added products.

Polyolefin graft modification methods mainly include: solution grafting, melt grafting, radiation grafting, solid phase grafting, and suspension grafting. Among them, the first three methods need to be carried out under high-energy radiation or high temperature conditions, and polyolefin molecular chains are prone to chain scission and degradation, which makes the performance of the grafted modified material significantly decreased. The solid phase grafting method and the suspension grafting method carry out the grafting reaction at a lower temperature, so that the degradation degree of polyolefin is significantly reduced. Among them, the aqueous phase suspension solid phase grafting method suspends polyolefin in a layer containing Grafting in the aqueous solution of grafting monomers has the advantages of low reaction temperature, short reaction time, low production cost, simple reaction process, easy post-treatment, etc., and can effectively overcome the material bonding that is prone to occur in conventional solid-phase grafting methods. , Stirring and uneven heat transfer and other deficiencies.

Currently commonly used polyolefin graft modified monomers mainly include maleic anhydride (MAH), glycidyl methacrylate (GMA), acrylic acid (AA), methyl methacrylate (MMA), N-cyclohexyl maleic acid Imide, etc. These monomers are often highly toxic, have a low boiling point, are volatile or sublimable, and cause damage to the eyes and skin of field operators, and there are great difficulties in the actual production process.

The applicant of the present invention has developed a class of unsaturated carboxylic acid monomers, and applied it to the graft modification of polypropylene and linear low-density polyethylene, and prepared novel polypropylene and linear low-density polyethylene with high grafting rate. Ethylene graft copolymers, related public documents see the applicant's Chinese patent application documents CN201210066164.5 (applied on March 14, 2012), CN201210417754.8 (applied on October 29, 2012), CN201310125153.4 ( Application on April 11, 2013) and CN201310131982.3 (application on April 16, 2013). Compared with traditional polyolefin graft monomers (such as maleic anhydride, glycidyl methacrylate, acrylic acid, methacrylic acid, methyl methacrylate, etc.), this type of unsaturated carboxylic acid monomer has non-toxic, It is non-volatile or sublimable and has good biocompatibility due to the amino acid residues. These advantages are expected to make polyolefins have a wider application prospect in the biological field.

In the above-mentioned Chinese invention patent application documents, CN201210066164.5 (applied on March 14, 2012) and CN201310125153.4 (applied on April 11, 2013) prepared polypropylene with high grafting rate and linear low-density polyethylene graft copolymers, but when using this method to prepare high-density polyethylene graft copolymers, graft copolymers cannot be obtained, which may be due to the regular structure and high crystallinity of high-density polyethylene, which are not The proportion of the crystalline region is significantly lower than that of polypropylene and low-density polyethylene, and the grafting reaction generally occurs in the amorphous region of the matrix resin.

Contents of the invention

The object of the present invention is to provide a kind of method that can improve grafting reaction activity, and then improve the grafting rate of grafted product to improve polyolefin grafting unsaturated carboxylic acid monomer grafting rate.

The purpose of the present invention is achieved like this:

(1) Preparation of unsaturated carboxylic acid monomers by reacting acryloyl chloride or methacryloyl chloride with corresponding amino acids under basic conditions;

(2) Dissolving 5-25 parts of unsaturated carboxylic acid monomer and 5-25 parts of cerium trichloride or its hydrate in 60 parts of N,N dimethylformamide (DMF) or water at the same time, Stir for 30 minutes to obtain solution A; dissolve 2 parts of dibenzoyl peroxide (BPO) in 10-20 parts of interface agent xylene to obtain solution B; mix 100 parts of polyolefin particles with 5-25 parts of the second grafted single Solid styrene (St) was placed in a reaction vessel containing 300 parts of water, and stirred to suspend polyolefin particles uniformly in the water; solution A and solution B were added to the reaction vessel, and stirred at 60°C for 1.5h under a nitrogen atmosphere, React at 95°C for 2 hours, then cool, wash, filter, and dry to obtain the final grafted product.

The present invention may also include:

1. The amino acids include proline, glycine, phenylglycine, phenylalanine or valine, and the corresponding unsaturated carboxylic acid monomers are 1-acryloylpyrrolidine-2-carboxylic acid, 1-methyl Acryloylpyrrolidine-2-carboxylic acid, 2-acrylamidoacetic acid, 2-methacrylamidoacetic acid, 2-acrylamido-2-phenylacetic acid, 2-methacrylamido-2-phenyl Acetic acid, 2-acrylamido-3-phenylpropionic acid, 2-methacrylamido-3-phenylpropionic acid, 2-acrylamido-3-methylbutyric acid or 2-methacrylamido -3-Methylbutanoic acid.

2. The molar ratio of unsaturated carboxylic acid monomer to cerium trichloride or its hydrate is 1:3 to 3:1, preferably 1:1.

3. The weight ratio of the unsaturated carboxylic acid grafting monomer to the auxiliary grafting monomer styrene is 3:7 to 7:3, preferably 1:1.

The invention applies a variety of (meth)acrylamide derivative-like unsaturated carboxylic acid monomers to the graft modification of polyolefins (including polypropylene, linear low-density polyethylene, and high-density polyethylene), and adopts water phase suspension The solid phase grafting method adds cerium trichloride or its hydrate to the reaction system to prepare a polyolefin graft copolymer with high grafting rate and good biocompatibility.

In the present invention, when preparing unsaturated carboxylic acid functionalized polyolefin, cerium trichloride and its hydrate are added in the reaction system. Due to the unique valence electron layer structure of rare earth element cerium, it can be combined with unsaturated carboxylic acid monomer structure. The coordination between the carbonyl groups activates the monomer, thus increasing its grafting reactivity, and then increasing the grafting rate of the grafted product.

In order to obtain a pure grafted product, the present invention uses methanol and acetone to extract the grafted product respectively, and the purpose is to remove homopolymers, copolymers, unreacted monomers and other additives of grafted monomers and styrene , and then vacuum-dried to obtain the final grafted product.

Compared with the prior art, the present invention has the following characteristics:

1) The present invention adds cerium trichloride or its hydrate in polyolefin grafted unsaturated carboxylic acid system, utilizes the coordination effect of rare earth element cerium and unsaturated carboxylic acid monomer, has improved the reactivity of monomer, extremely Greatly improved the graft ratio of polyolefin (especially high density polyethylene) graft copolymer;

2) In the present invention, for the first time, methacrylamide derivative-like unsaturated carboxylic acid monomers are applied to the functional modification of polyolefins, and functionalized polyolefin copolymers with high grafting rates are obtained. Such unsaturated carboxylic acid monomers The body is similar to the acrylamide derivative unsaturated carboxylic acid (seeing the related patent application of the inventor) that the inventor has reported, and has the advantages of non-toxicity and good biocompatibility. The functional modification of olefins has greatly improved the application prospects of polyolefins in the biological field.

Description of drawings

Fig. 1 is the infrared spectrogram of HDPE and unsaturated carboxylic acid monomer grafted HDPE. In the figure a is the infrared spectrum of HDPE, b is the infrared spectrum of unsaturated carboxylic acid monomer grafted HDPE, c is the infrared spectrum of unsaturated carboxylic acid monomer grafted HDPE with cerium trichloride hydrate .

detailed description

Below in conjunction with embodiment the present invention is described in further detail. The scope of the present invention is not limited by these examples.

Comparative example 1:

Dissolve 10 parts by weight of unsaturated carboxylic acid monomer 1-methacrylamido-2-phenylacetic acid in 60 parts of N,N-dimethylformamide (DMF), 2 parts of diphenyl peroxide Acyl (BPO) was dissolved in 20 parts of interface agent xylene; 100 parts of high-density polyethylene (HDPE) particles and 10 parts of the second graft monomer styrene (St) were placed in a reaction vessel containing 300 parts of water, Stir to suspend HDPE particles uniformly in water; add the unsaturated carboxylic acid monomer solution and BPO solution into the reaction vessel through a syringe, stir for 1.5h at 60°C under a nitrogen atmosphere, react at 95°C for 2 hours, then cool and wash , filtered, extracted with methanol and acetone respectively, and vacuum-dried to obtain the final grafted product with a grafting rate of 2.9%.

The invention adopts a chemical titration method to measure the grafting ratio of the unsaturated carboxylic acid monomer grafted to HDPE. The specific method is as follows: firstly, the grafted product was extracted with acetone and methanol for 12 hours to remove possible residual styrene and unsaturated carboxylic acid homopolymer. Accurately weigh a certain amount (m) of the grafted product, dissolve it in an appropriate amount of xylene, add ₁ mL of excess KOH-ethanol standard solution V with a concentration of C ₁ , and reflux at 120°C for 1 h. After the reaction is sufficient, the excess alkali is back-dropped with the acetic acid _- xylene standard solution whose concentration is _C2 , and the consumption volume is V2 mL, and the grafting rate is calculated according to the following formula (three parallel samples are measured for each measurement):

$\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; V</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 1000</span>}\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

In the formula, M is the molar mass of the unsaturated carboxylic acid monomer.

It can be known by calculation that the grafting ratio of the unsaturated carboxylic acid monomer grafted to HDPE in this embodiment is 2.9%.

Example 1:

10 parts by weight of unsaturated carboxylic acid monomer 1-methacrylamido-2-phenylacetic acid and 10 parts by weight of cerium trichloride heptahydrate (CeCl ₃ 7H ₂ O) were simultaneously dissolved in 60 parts of N, In N-dimethylformamide (DMF), stir for 30 minutes (solution 1); dissolve 2 parts of dibenzoyl peroxide (BPO) in 20 parts of interface agent xylene (solution 2); Density polyethylene (HDPE) particles and 10 parts of the second graft monomer styrene (St) are placed in a reaction vessel containing 300 parts of water, and stirred to suspend the HDPE particles in the water evenly; pass solution 1 and solution 2 through the syringe Add it into the reaction vessel, stir for 1.5h at 60°C under a nitrogen atmosphere, react at 95°C for 2 hours, then cool, wash, filter, extract with methanol and acetone, and dry in vacuum to obtain the final grafted product. Its graft rate is 8.1%.

Comparative example 2:

6 parts of unsaturated carboxylic acid monomer 2-acrylamidoacetic acid are dissolved in 60 parts of water, 2 parts of dibenzoyl peroxide (BPO) are dissolved in 10 parts of interface agent xylene respectively; Propylene (PP) particles and 14 parts of the second graft monomer styrene (St) are placed in a reaction vessel containing 300 parts of water, stirred to suspend the PP particles uniformly in water; the unsaturated carboxylic acid monomer solution and BPO The solution was added into the reaction vessel through a syringe, stirred for 1.5 h at 60°C under a nitrogen atmosphere, reacted at 95°C for 2 hours, then cooled, washed, filtered, extracted with methanol and acetone, and dried in vacuum to obtain the final Branch product, its graft rate is 2.4%.

Example 2:

6 parts by weight of unsaturated carboxylic acid monomer 2-acrylamidoacetic acid and 6 parts of CeCl ₃ ·7H ₂ O were simultaneously dissolved in 60 parts of water and stirred for 30 minutes (solution 1); 2 parts of diphenyl peroxide Acyl (BPO) was dissolved in 10 parts of interface agent xylene (solution 2); 100 parts of PP particles and 14 parts of the second graft monomer styrene (St) were placed in a reaction vessel containing 300 parts of water, and stirred to PP particles are uniformly suspended in water; add solution 1 and solution 2 into the reaction vessel through a syringe, stir at 60°C for 1.5h under a nitrogen atmosphere, react at 95°C for 2 hours, then cool, wash, filter, and wash with methanol and Extracted with acetone and dried in vacuum, the final grafted product can be obtained with a grafting rate of 3.1%.

Comparative example 3:

14 parts by weight of unsaturated carboxylic acid monomer 2-acrylamido-3-phenylpropionic acid are dissolved in 60 parts of N,N-dimethylformamide (DMF), 2 parts of dibenzoyl peroxide (BPO) was dissolved in 20 parts of interface agent xylene; 100 parts of linear low density polyethylene (LLDPE) particles and 6 parts of the second graft monomer styrene (St) were placed in a reaction vessel containing 300 parts of water, and stirred Suspend the LLDPE particles uniformly in water; add the unsaturated carboxylic acid monomer solution and BPO solution into the reaction vessel through a syringe, stir for 1.5h at 60°C under a nitrogen atmosphere, react at 95°C for 2 hours, and then cool, wash, Filtration, extraction with methanol and acetone, and vacuum drying to obtain the final grafted product with a grafting rate of 5.0%.

Example 3:

14 parts by weight of unsaturated carboxylic acid monomer 2-acrylamido-3-phenylpropionic acid and 14 parts of CeCl ₃ ·7H ₂ O were simultaneously dissolved in 60 parts of N,N-dimethylformamide (DMF) , stirred for 30 minutes (solution 1); 2 parts of dibenzoyl peroxide (BPO) were dissolved in 20 parts of interface agent xylene (solution 2); 100 parts of LLDPE particles and 6 parts of the second graft monomer benzene Ethylene (St) was placed in a reaction vessel containing 300 parts of water, and stirred to suspend the LLDPE particles uniformly in the water; solution 1 and solution 2 were added to the reaction vessel through a syringe, and stirred at 60°C for 1.5h under a nitrogen atmosphere, 95 After reacting at ℃ for 2 hours, cooling, washing, filtering, extracting with methanol and acetone respectively, and vacuum drying, the final grafted product can be obtained with a grafting rate of 8.1%.

Comparative example 4:

Dissolve 6 parts by weight of unsaturated carboxylic acid monomer L-1-acryloylpyrrolidine-2-carboxylic acid in 60 parts of N,N-dimethylformamide (DMF), 2 parts of diphenyl peroxide Acyl (BPO) was dissolved in 10 parts of interface agent xylene; 100 parts of PP particles and 14 parts of the second graft monomer styrene (St) were placed in a reaction vessel containing 300 parts of water, and stirred to make the PP particles uniform Suspend in water; Add the unsaturated carboxylic acid monomer solution and BPO solution into the reaction vessel through a syringe, stir at 60°C under a nitrogen atmosphere for 1.5h, react at 95°C for 2 hours, then cool, wash, filter, and use methanol and acetone extraction, vacuum drying, the final grafted product can be obtained, and its grafting rate is 4.0%.

Example 4:

Dissolve 6 parts by weight of unsaturated carboxylic acid monomer L-1-acryloylpyrrolidine-2-carboxylic acid and 6 parts of CeCl ₃ ·7H ₂ O in 60 parts of N,N-dimethylformamide (DMF ), stirred for 30 minutes (solution 1); 2 parts of dibenzoyl peroxide (BPO) were dissolved in 10 parts of interface agent xylene (solution 2); 100 parts of PP particles were mixed with 14 parts of the second grafted single Solid styrene (St) was placed in a reaction vessel containing 300 parts of water, and stirred to suspend PP particles uniformly in the water; solution 1 and solution 2 were added to the reaction vessel through a syringe, and stirred at 60°C for 1.5h under a nitrogen atmosphere , reacted at 95°C for 2 hours, then cooled, washed, filtered, extracted with methanol and acetone, and dried in vacuum to obtain the final grafted product with a grafting rate of 5.2%.

Comparative example 5:

Dissolve 6 parts of unsaturated carboxylic acid monomer 2-acrylamido-3-phenylpropionic acid in 60 parts of N, N-dimethylformamide (DMF), 2 parts of dibenzoyl peroxide (BPO) was dissolved in 20 parts of interface agent xylene; 100 parts of HDPE particles and 14 parts of the second graft monomer styrene (St) were placed in a reaction vessel containing 300 parts of water, and the HDPE particles were evenly suspended by stirring in water; add the unsaturated carboxylic acid monomer solution and BPO solution into the reaction vessel through a syringe, stir at 60°C for 1.5h under a nitrogen atmosphere, react at 95°C for 2 hours, then cool, wash, filter, and wash with methanol and Acetone extraction, vacuum drying, the final grafted product can be obtained, and its grafting rate is 2.3%.

Example 5:

Dissolve 6 parts by weight of unsaturated carboxylic acid monomer 2-acrylamido-3-phenylpropionic acid and 6 parts of CeCl ₃ ·7H ₂ O in 60 parts of N,N-dimethylformamide (DMF) , stirred for 30 minutes (solution 1); 2 parts of dibenzoyl peroxide (BPO) were dissolved in 20 parts of interface agent xylene (solution 2); 100 parts of HDPE particles were mixed with 14 parts of the second graft monomer Styrene (St) was placed in a reaction vessel containing 300 parts of water, and stirred to suspend HDPE particles uniformly in the water; solution 1 and solution 2 were added to the reaction vessel through a syringe, and stirred at 60°C for 1.5h under a nitrogen atmosphere, React at 95°C for 2 hours, then cool, wash, filter, extract with methanol and acetone, and dry in vacuum to obtain the final grafted product with a grafting rate of 4.1%.

Claims (8)

1. the method improving polyolefin graft unsaturated carboxylic acid monomer percent grafting, is characterized in that:

(1) unsaturated carboxylic acid monomer is prepared by acryloyl chloride or methacrylic chloride and the reaction in the basic conditions of corresponding aminoacid；

(2) cerous chloride or its hydrate of unsaturated carboxylic acid monomer that weight is 5-25 part and 5-25 part are dissolved in 60 parts of DMFs or water simultaneously, stir and obtain solution A in 30 minutes；2 parts of dibenzoyl peroxides are dissolved in 10-20 part interfacial agents dimethylbenzene and obtain solution B；Being placed in the reaction vessel containing 300 parts of water by 100 parts of polyolefin particles and 5-25 part the second grafted monomers styrene, stirring makes polyolefin particles suspend in water equably；Joining in reaction vessel by solution A and solution B, stirring 1.5h under 60 DEG C of nitrogen atmospheres, 95 DEG C are reacted 2 hours, then through cooling, washing, filtration, dry, namely obtain final graft product.

2. the method for raising polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 1, is characterized in that: the mol ratio of unsaturated carboxylic acid monomer and cerous chloride or its hydrate is 1:3 to 3:1.

3. the method for raising polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 2, is characterized in that: the mol ratio of unsaturated carboxylic acid monomer and cerous chloride or its hydrate is 1:1.

4. the method improving polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 1,2 or 3, is characterized in that: unsaturated carboxylic acid graft monomer and the auxiliary cinnamic weight ratio of grafted monomers are 3:7 to 7:3.

5. the method for raising polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 4, is characterized in that: unsaturated carboxylic acid graft monomer and the auxiliary cinnamic weight ratio of grafted monomers are 1:1.

6. according to claim 1, the method improving polyolefin graft unsaturated carboxylic acid monomer percent grafting described in 2 or 3, it is characterized in that: described aminoacid includes proline, glycine, phenylglycine, phenylalanine or valine, corresponding unsaturated carboxylic acid monomer respectively 1-acryloyl pyrrolidine-2-carboxylic acid, 1-methacryl pyrrolidine-2-carboxylic acid, 2-acrylamide guanidine-acetic acid, 2-methacryl glycine, 2-acrylamido-2-phenylacetic acid, 2-methacryl amido-2-phenylacetic acid, 2-acrylamido-3-phenylpropionic acid, 2-methacryl amido-3-phenylpropionic acid, 2-acrylamido-3 Methylbutanoic acid or 2-methacryl amido-3 Methylbutanoic acid.

7. the method for raising polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 4, it is characterized in that: described aminoacid includes proline, glycine, phenylglycine, phenylalanine or valine, corresponding unsaturated carboxylic acid monomer respectively 1-acryloyl pyrrolidine-2-carboxylic acid, 1-methacryl pyrrolidine-2-carboxylic acid, 2-acrylamide guanidine-acetic acid, 2-methacryl glycine, 2-acrylamido-2-phenylacetic acid, 2-methacryl amido-2-phenylacetic acid, 2-acrylamido-3-phenylpropionic acid, 2-methacryl amido-3-phenylpropionic acid, 2-acrylamido-3 Methylbutanoic acid or 2-methacryl amido-3 Methylbutanoic acid.

8. the method for raising polyolefin graft unsaturated carboxylic acid monomer percent grafting according to claim 5, it is characterized in that: described aminoacid includes proline, glycine, phenylglycine, phenylalanine or valine, corresponding unsaturated carboxylic acid monomer respectively 1-acryloyl pyrrolidine-2-carboxylic acid, 1-methacryl pyrrolidine-2-carboxylic acid, 2-acrylamide guanidine-acetic acid, 2-methacryl glycine, 2-acrylamido-2-phenylacetic acid, 2-methacryl amido-2-phenylacetic acid, 2-acrylamido-3-phenylpropionic acid, 2-methacryl amido-3-phenylpropionic acid, 2-acrylamido-3 Methylbutanoic acid or 2-methacryl amido-3 Methylbutanoic acid.