CN103304755B - A kind of antibacterial polypropylene block copolymer and preparation method thereof and material modified containing this segmented copolymer - Google Patents

Abstract

The invention relates to an antibacterial polypropylene block copolymer, a preparation method thereof, and a modified material containing the antibacterial polypropylene block copolymer. Described antibacterial polypropylene block copolymer, its general formula is S-I-S, and I is the polypropylene chain segment of hydrophilic body, and S is the antibacterial functional chain segment; The antibacterial functional chain segment is polymethacrylic acid quaternary ammonium salt, polyacrylic acid chitosan , poly-p-vinylbenzyl tributylphosphonium chloride or polyvinylpyridine quaternary ammonium salt; the molecular weights of the polypropylene segment of the substrate and the antibacterial functional segment are respectively 1000-20000 g/mol. In the present invention, the antibacterial polypropylene block copolymer formed by combining the matrix-phile polypropylene segment and the specific antibacterial functional segment solves the problems existing in the prior art; the process is simple and the cost is low; The adhesion of the copolymer is greatly improved, it is not easy to fall off, and the durability is good, so that the antibacterial performance has long-term effect without affecting the mechanical properties of the matrix material.

Description

A kind of antibacterial polypropylene block copolymer and its preparation method, and the modified material containing the block copolymer

technical field

The invention relates to the field of copolymers, in particular to an antibacterial polypropylene block copolymer, a preparation method thereof, and a modified material containing the antibacterial polypropylene block copolymer.

Background technique

As a general-purpose thermoplastic, polypropylene (PP) has the characteristics of low density, good heat resistance, easy processing and molding, high heat distortion temperature, and low price, making it widely used. Especially in recent years, with the improvement and development of plastic modification technology, polypropylene has been widely used in food packaging, textiles, biomedicine, medical equipment and other fields. These fields must avoid bacterial or fungal infection and the spread of diseases. Therefore, the surface antibacterial modification of polypropylene materials has practical value and significance.

The surface antibacterial modification methods of polypropylene materials can be divided into two categories: surface grafting and blending. Surface graft modification is to graft antibacterial groups or polymer chain segments to the surface of polypropylene materials by chemical grafting, surface photografting or radiation grafting. Although this method has good antibacterial modification effect and long-term effect, the process is complicated and the cost is high, and it is easy to leave chemicals on the surface of the product.

Blending modification refers to adding an antibacterial agent to polypropylene to achieve antibacterial modification. Antibacterial agents can include inorganic antibacterial agents such as silver series and titanium series, and organic antibacterial agents such as quaternary ammonium salts, alcohols, phenols, and biguanides. Although inorganic antibacterial agents have the advantages of high antibacterial efficiency, good heat resistance, and safe use, they have defects such as high price, delayed antibacterial effect, great influence on the mechanical properties of PP matrix resin, and easy surface desorption and failure. Small molecular organic antibacterial agents have certain toxicity, and are easy to volatilize and lose, and have poor long-term effect; although macromolecular antibacterial agents have the advantages of good antibacterial performance, non-volatility, and will not penetrate into human or animal epidermis, but due to macromolecular antibacterial agents and The structure and properties of polypropylene are quite different, the adhesion to PP is poor, it is easy to lose, and the antibacterial long-term effect is poor. When the amount added is large, it is easy to affect the mechanical properties of the matrix material.

Based on the needs of industry and practical applications, it is necessary to find a polypropylene surface antibacterial method with simple synthesis process, high antibacterial properties, and good durability without affecting the mechanical properties of the matrix material, and its corresponding block copolymers and modified Material.

Contents of the invention

In order to solve the problems in the prior art, one of the objectives of the present invention is to provide an antibacterial polypropylene block copolymer.

Another object of the present invention is to provide a preparation method of the antibacterial polypropylene block copolymer.

Another object of the present invention is to provide a modified material containing antibacterial polypropylene block copolymer.

The antibacterial polypropylene block copolymer provided by the present invention has a general formula of S-I-S, I is a substrate polypropylene segment, and S is an antibacterial functional segment; the antibacterial functional segment is: polymethacrylic acid quaternary ammonium salt, Chitosan polyacrylate, poly(p-vinylbenzyltributylphosphonium chloride) or polyvinylpyridine quaternary ammonium salt.

Further, the quaternary ammonium polymethacrylate is: N,N-dimethylaminoethyl polymethacrylate quaternary ammonium salt.

Wherein, the molecular weights of the matrix-phile polypropylene segment and the antibacterial functional segment are respectively 1000-20000 g/mol, preferably 1000-8000 g/mol.

Further, the number of repeating units of the polypropylene segment of the base-phile is 10-300, and the number of repeating units of the antibacterial functional segment is 20-500.

That is to say, the antibacterial polypropylene block copolymer provided by the present invention has the structure shown in the following formula:

Wherein, m is the number of repeating units of the polypropylene segment of the matrix-phile, m=10-300; n is the number of repeating units of the antibacterial functional segment, n=20-500.

R ₁ is H or methyl; R ₂ is COOCH ₂ CH ₂ N ⁺ (CH ₃ ) ₂ (CH ₂ CH ₃ )Cl ^- , COO chitosan, pyridine quaternary ammonium salt or benzyl tributylphosphine chloride.

Wherein, the molecular weight of the antibacterial polypropylene block copolymer is 2000-40000 g/mol, preferably 2000-16000 g/mol.

The preparation method of the antibacterial polypropylene block copolymer provided by the present invention comprises: the polymerization reaction of the functional monomer is initiated by the polypropylene segment of the substrate, the atom transfer radical polymerization method is adopted, and cuprous chloride is used as the catalyst to Bipyridine is used as a ligand, the reaction temperature is 50-150°C, and the reaction time is 4-24 hours, and the antibacterial polypropylene block copolymer (containing antibacterial functional chain segment) is directly prepared; or after further quaternization or chitosanization Sugar reaction to prepare antibacterial polypropylene block copolymer (containing antibacterial functional segment).

Wherein, the functional monomer is: acrylic acid, N,N-dimethylaminoethyl methacrylate, p-vinylbenzyl tributylphosphine chloride or vinylpyridine, etc.

Among them, the reaction temperature is preferably 100°C. The reaction time is preferably 12 hours.

Wherein, the preparation method of the arophilic polypropylene segment comprises: pyrolysis of polypropylene by pyrolysis or cracking under the action of concentrated nitric acid, and chemical modification of end groups to prepare double-terminal halogen polypropylene (i.e. arophilic polypropylene chain segment).

Further, the preparation method of the polypropylene segment of the arophilic body comprises: cracking polypropylene at 350°C under the condition of nitrogen protection to prepare polypropylene with double bonds at the end, and then combining the polypropylene with double bonds at the end with hydrogen chloride or bromide Hydrogen addition reaction, the preparation of double-terminal halogen (chlorine or bromine) polypropylene.

Alternatively, the preparation method of the polypropylene segment of the arophilic body comprises: heating polypropylene and concentrated nitric acid to reflux at 110°C, stirring, reacting for 16 hours, cooling, filtering, and removing residual nitric acid to obtain carboxyl-terminated polypropylene; Carboxylated polypropylene is heated and dissolved in cyclohexanone, added epichlorohydrin and tetrabutylammonium bromide, refluxed, stirred for 6 hours, cooled, filtered, and extracted with ethanol to obtain double-terminal halogen polypropylene (with terminal chlorine low molecular weight polypropylene).

The present invention is described in further detail below: the polypropylene chain segment of the matrix-phile of the present invention can be obtained by pyrolysis or cracking under the action of concentrated nitric acid by polypropylene, and the polypropylene chain segment of the matrix-phile prepared by the above method can control its molecular weight and It has a molecular weight distribution, and the end of the molecular chain contains double bonds or carboxyl functional groups that can be further reacted. After further end group reactions, halogens such as chlorine and bromine are introduced at the molecular ends of polypropylene to initiate atom transfer radical polymerization of functional monomers. Directly prepare block copolymers containing antibacterial polymer functional segments; or through further quaternization or chitosan reaction, prepare block copolymers containing antibacterial polymer functional segments, which are used as special Modification additives to enhance the surface antimicrobial properties of polypropylene.

The existence of the molecular matrix segment of the modifier in the present invention can improve the adhesion of the modifier on the surface of polypropylene, prevent the modifier from falling off due to friction or water erosion of the material, and maintain the long-acting and stable antibacterial modification effect. Persistence.

According to this patent, the antibacterial functional segment of the antibacterial polypropylene block copolymer has antibacterial properties. In the selection of the antibacterial functional segment, polymers with antibacterial properties are mainly used, including N, N-dimethylaminoethyl methacrylate quaternary ammonium salt, polyacrylic acid chitosan, poly-p-vinylbenzyl three Polymer segments with antibacterial properties such as butylphosphonium chloride or polyvinylpyridine quaternary ammonium salt. The molecular weight of the functional segment is in the range of hundreds to tens of thousands, and the optimum molecular weight is 1000-8000. The antibacterial polymethacrylic acid N, N-dimethylaminoethyl ester quaternary ammonium salt, polyacrylic acid chitosan, polyvinyl benzyl tributyl phosphorus chloride or polyvinylpyridine quaternary ammonium salt can pass Atom Transfer Radical Polymerization directly introduces the two ends of the polypropylene segment of the matrix, or obtains it through further reaction.

The modified material containing the antibacterial polypropylene block copolymer provided by the present invention is to mix the antibacterial polypropylene block copolymer with the polypropylene base material by blending, and the antibacterial polypropylene block copolymer The amount of added, by mass, is 0.1% to 20% of the mass of the polypropylene substrate.

Further, the addition amount of the antibacterial polypropylene block copolymer is 1%-10% of the mass of the polypropylene substrate, more preferably 1%-5%.

Due to the special design of the structure of the present invention, the antibacterial polypropylene block copolymer has amphiphilicity, and the copolymer can be modified by blending, and can be well migrated and adsorbed to the polypropylene during processing and molding. The surface of the propylene material makes the modified material have excellent antibacterial properties, which can avoid the infection of bacteria or fungi on the surface of polypropylene products and the spread of diseases; at the same time, due to the existence of polypropylene chain segments, the macromolecule ) is difficult to detach from the surface of the polypropylene material, and has good long-term performance; in addition, due to the small amount added, most of the antibacterial modifier (that is, the copolymer) migrates to the surface of the product without affecting the mechanical properties of the product.

In a word, the antibacterial polypropylene block copolymer formed by combining the matrix-philic polypropylene segment and the specific antibacterial functional segment in the present invention solves the problems existing in the prior art. The process is simple and the cost is low; the adhesion of the antibacterial polypropylene block copolymer in the modified material is greatly improved, it is not easy to fall off, and the durability is good, so that the antibacterial performance has long-lasting effect without affecting the mechanical properties of the matrix material. It has great application prospect and market value.

Description of drawings

Fig. 1 is the infrared spectrogram of the polypropylene block copolymer with bactericidal function obtained according to Example 4.

Fig. 2 is the thermal weight loss diagram of the polypropylene block copolymer with bactericidal function obtained according to Example 2.

Fig. 3 is a schematic diagram of the results of the solvent scouring resistance test of the modified material obtained according to Example 4, wherein broken lines a and b respectively represent the surface content of the modified material before and after the solvent ethanol scouring test.

detailed description

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

Crack 50g of isotactic polypropylene at 350°C under the condition of nitrogen protection to prepare polypropylene with terminal double bonds, and then carry out addition reaction of terminal double bond polypropylene with hydrogen chloride or hydrogen bromide to obtain double-terminal halogen (chlorine or bromine) polypropylene.

Take 30g of self-made polypropylene with terminal chlorine (or terminal bromine) functionalization, dissolve it in xylene, add CuCl and bipyridine as catalyst and ligand respectively, and add 50ml of acrylic acid. Electromagnetically stirred in a constant temperature oil bath at 100°C for 12 hours, cooled, and filtered. The solid product was extracted with ethanol for 48h and dried for later use.

Weigh 30g of polypropylene/polyacrylic acid block copolymer (without bactericidal function) and dissolve it in xylene, add 10g of chitosan, and react under reflux for 4h. Cool, filter and dry to prepare polypropylene/polyacrylic acid chitosan block copolymer with bactericidal function.

The molecular weight of the polypropylene segment in the block copolymer prepared in this embodiment is 6000g/mol, and the molecular weight of the polyacrylic acid chitosan segment is 7800g/mol.

The polypropylene/polyacrylic acid chitosan block copolymer with bactericidal function synthesized above is blended with polypropylene resin to prepare modified materials, and the addition amount of polypropylene/polyacrylic acid chitosan block copolymer with bactericidal function The modified material is 1% of the weight of polypropylene resin, which can kill 65% of Escherichia coli and 80% of Staphylococcus aureus. When the antibacterial modifier (the above-mentioned polypropylene/polyacrylic acid chitosan block copolymer with bactericidal function) is added in an amount (weight content) of 4%, it can kill more than 90% of Escherichia coli and 80% of golden yellow staphylococcus. Soaked in water or ethanol for 48 hours, its antibacterial properties remain unchanged, or even slightly improved, reflecting long-acting and persistent.

Example 2

Take 30g of self-made polypropylene with terminal chlorine functionalization, dissolve it in xylene, add CuCl and bipyridine as catalyst and ligand respectively, and add 10g of p-vinylbenzyl tributylphosphine chloride. Electromagnetically stirred in a constant temperature oil bath at 100°C for 12 hours, cooled, and filtered. The solid product was extracted with ethanol for 48 hours and dried to obtain a polypropylene block copolymer containing antibacterial poly(p-vinylbenzyltributylphosphorus chloride) segments (the thermal weight loss diagram is shown in Figure 2).

The molecular weight of the polypropylene segment in the block copolymer prepared in this embodiment is 4000 g/mol, and the molecular weight of the poly-p-vinylbenzyl tributylphosphorous chloride segment is 5400 g/mol.

The above-mentioned synthesized polypropylene block copolymer with antibacterial properties is blended with polypropylene resin to prepare a modified material, and the added amount of the antibacterial polypropylene block copolymer is 1% of the weight of the polypropylene resin. , can kill 60% of Escherichia coli and 75% of Staphylococcus aureus. When the antibacterial modifier (the above-mentioned bactericidal polypropylene block copolymer) is added in an amount (weight content) of 5%, it can kill more than 98% of Escherichia coli and 95% of Staphylococcus aureus. After soaking in water or ethanol for 48 hours, its antibacterial properties remained unchanged or even slightly improved.

Example 3

Take 30g of self-made polypropylene with terminal chlorine functionalization, dissolve it in xylene, add CuCl and bipyridine as catalyst and ligand respectively, and add 10g of vinylpyridine. Electromagnetically stirred in a constant temperature oil bath at 100°C for 12 hours, cooled, and filtered. The solid product was extracted with ethanol for 48 hours and dried to obtain a polypropylene block copolymer containing polyvinylpyridine segments (no antibacterial properties). The block copolymer is quaternized with dimethyl sulfate to obtain a polypropylene block copolymer (with antibacterial properties) containing polyvinylpyridine quaternary ammonium salt segments.

The molecular weight of the polypropylene segment in the block copolymer prepared in this embodiment is 7500 g/mol, and the molecular weight of the polyvinylpyridine quaternary ammonium salt segment is 4800 g/mol.

The above-mentioned synthesized polypropylene block copolymer with antibacterial properties is blended with polypropylene resin to prepare a modified material, and the addition of the antibacterial polypropylene block copolymer is a modified material of 2% of the weight of the polypropylene resin , can kill 70% of Escherichia coli and 60% of Staphylococcus aureus. When the antibacterial modifier (the above-mentioned bactericidal polypropylene block copolymer) is added in an amount (weight content) of 4%, it can kill more than 95% of Escherichia coli and 90% of Staphylococcus aureus. After soaking in water or ethanol for 48 hours, its antibacterial properties remained unchanged or even slightly improved.

Example 4

Heat 50g of isotactic polypropylene and 20ml of concentrated nitric acid to reflux at 110°C, stir electromagnetically, cool and filter after reacting for 16 hours, rinse with water and acetone to pH ≈ 6, and remove residual nitric acid; the obtained solid is carboxyl-terminated polypropylene.

Heat and dissolve 30 g of self-made carboxy-terminated polypropylene in cyclohexanone, add 10 ml of epichlorohydrin and 0.6 g of catalyst tetrabutylammonium bromide. Reflux, magnetically stir for 6h, cool and filter. The solid was extracted with ethanol for 24 hours to obtain low molecular weight polypropylene with terminal chlorine, which was dried for later use.

Take 30g of self-made polypropylene with terminal chlorine functionalization, dissolve it in xylene, add CuCl and bipyridine as catalyst and ligand respectively, and add 50ml of N,N-dimethylaminoethyl methacrylate. Electromagnetically stirred in a constant temperature oil bath at 100°C for 12 hours, cooled, and filtered. The solid product was extracted with ethanol for 48h and dried for later use.

Weigh 30g of polypropylene/poly(N,N-dimethylaminoethyl methacrylate) block copolymer (without antibacterial properties) and dissolve it in xylene, add 10ml of excess ethyl bromide, and react under reflux for 4h. Cool, filter and dry. A polypropylene/polymethacrylic acid N,N-dimethylaminoethyl ester quaternary ammonium salt block copolymer with bactericidal function was obtained (the infrared spectrum is shown in Figure 1).

The molecular weight of the polypropylene segment in the block copolymer prepared in this example is 3500 g/mol, and the molecular weight of the poly(N,N-dimethylaminoethyl methacrylate quaternary ammonium salt) segment is 7600 g/mol.

The polypropylene block copolymer with bactericidal function synthesized above is blended with polypropylene resin to prepare a modified material, and the added amount of polypropylene block copolymer with bactericidal function is 1% of the weight of polypropylene resin. , can kill 35% of Escherichia coli and 10% of Staphylococcus aureus. When the antibacterial modifier (the above-mentioned polypropylene block copolymer with bactericidal function) is added in an amount (weight content) of 3%, it can kill more than 70% of Escherichia coli and 50% of Staphylococcus aureus. After soaking in water or ethanol for 48 hours, its antibacterial properties remained unchanged or even slightly improved.

The schematic diagram of the solvent scouring test results of the modified material obtained in this example is shown in Figure 3, which shows that the content of the block copolymer on the surface of the modified material is basically unchanged before and after ethanol scouring, and the modified material has long-lasting antibacterial effect sex.

Although the present invention has been described in detail with general descriptions and specific embodiments above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. a preparation method of antibacterial polypropylene block copolymer, it is characterized in that, the general formula of described antibacterial polypropylene block copolymer is S-I-S, and I is a matrix polypropylene segment, and S is an antibacterial functional segment; The antibacterial functional chain segment is: polymethacrylic acid quaternary ammonium salt, polyacrylic acid chitosan, polyvinyl benzyl tributyl phosphorus chloride or polyvinylpyridine quaternary ammonium salt; The molecular weights of the segment and the antibacterial functional segment are both 1000 to 20000 g/mol; the number of repeating units of the polypropylene segment of the substrate is 10 to 300, and the repeating unit of the antibacterial functional segment is 20 to 500; The preparation method of the antibacterial polypropylene block copolymer comprises: starting the functional monomer polymerization reaction by the polypropylene chain segment of the parent body, adopting the atom transfer radical polymerization method, using cuprous chloride as the catalyst, and using bipyridine as the ligand, The reaction temperature is 50-150 DEG C, the reaction time is 4-24 hours, and the antibacterial polypropylene block copolymer is prepared directly; or the antibacterial polypropylene block copolymer is prepared through further quaternization or chitosan reaction. 2. The preparation method according to claim 1, wherein the functional monomer is: acrylic acid, N,N-dimethylaminoethyl methacrylate, p-vinylbenzyl tributylphosphorous chloride or Vinylpyridine. 3. The preparation method according to claim 1 or 2, characterized in that the reaction temperature is 100°C and the reaction time is 12 hours. 4. according to the described preparation method of claim 1 or 2, it is characterized in that, the preparation method of described parent-phile polypropylene segment comprises: by polypropylene by high temperature cracking or cracking under the action of concentrated nitric acid, and chemical modification through end group sexual acquisition. 5. The preparation method according to claim 3, characterized in that, the preparation method of the polypropylene segment of the matrix-philic body comprises: by pyrolysis or cracking of polypropylene under the action of concentrated nitric acid, and obtained through end group chemical modification . 6. The preparation method according to claim 4, characterized in that, the preparation method of the polypropylene segment of the matrix-philic body comprises: cracking polypropylene at 350°C under nitrogen protection conditions to prepare polypropylene containing terminal double bonds, Addition reaction of double-bonded polypropylene with hydrogen chloride or hydrogen bromide to obtain it; or: heat polypropylene and concentrated nitric acid to reflux at 110°C, stir, react for 16 hours, then cool and filter to remove residual nitric acid. To obtain carboxyl-terminated polypropylene; then heat and dissolve carboxy-terminated polypropylene in cyclohexanone, add epichlorohydrin and tetrabutylammonium bromide, reflux, stir for 6 hours, cool, filter, and extract with ethanol. 7. The preparation method according to claim 5, characterized in that, the preparation method of the polypropylene segment of the hydrophilic body comprises: cracking polypropylene at 350° C. under nitrogen protection conditions to prepare polypropylene containing terminal double bonds, Addition reaction of double-bonded polypropylene with hydrogen chloride or hydrogen bromide to obtain it; or: heat polypropylene and concentrated nitric acid to reflux at 110°C, stir, react for 16 hours, then cool and filter to remove residual nitric acid. To obtain carboxyl-terminated polypropylene; then heat and dissolve carboxy-terminated polypropylene in cyclohexanone, add epichlorohydrin and tetrabutylammonium bromide, reflux, stir for 6 hours, cool, filter, and extract with ethanol. 8. The modified material containing the antibacterial polypropylene block copolymer prepared by the preparation method according to any one of claims 1 to 7 is to mix the antibacterial polypropylene block copolymer and polypropylene The base material is mixed, and the addition amount of the antibacterial polypropylene block copolymer is 0.1% to 20% of the mass of the polypropylene base material by mass. 9. The modified material according to claim 8, characterized in that the amount of the antibacterial polypropylene block copolymer added is 1% to 10% of the mass of the polypropylene substrate by mass. 10. The modified material according to claim 9, characterized in that the amount of the antibacterial polypropylene block copolymer added is, by mass, 1% to 5% of the mass of the polypropylene substrate.