阅读说明：本技术 一种通过复合引发体系合成***树胶高聚物的方法 (Method for synthesizing gum arabic high polymer by composite initiation system ) 是由 郑洁 唐晓旻 于 2020-07-09 设计创作，主要内容包括：本发明公开了一种通过复合引发体系合成阿拉伯树胶高聚物的方法。在该方法中以阿拉伯树胶、丙烯酰胺(AM)为原料；将阿拉伯树胶溶于蒸馏水配成水溶液,并在恒温条件下调节溶液pH值；用真空密封袋包装后采用高静水压技术进行凝胶化处理,再通过超声波处理获得阿拉伯树胶纳米颗粒。加入AM和蒸馏水,用超高速均化器对混合物进行均质化处理；加入光引发剂偶氮二异丁咪唑啉盐酸盐(VA-044)和热引发剂硝酸铈胺(CAN),氮气驱氧密封后将反应器放入透明恒温箱,并用紫外灯照射,采用光热协同引发的方式引发聚合反应,熟化提纯后即得一种通过复合引发体系合成的阿拉伯树胶高聚物。本发明所得的阿拉伯树胶高聚物具有高转化率,是水处理应用中的高效聚合物。(The invention discloses a method for synthesizing a gum arabic high polymer by a composite initiation system. In the method, Arabic gum and Acrylamide (AM) are used as raw materials; dissolving Arabic gum in distilled water to prepare an aqueous solution, and adjusting the pH value of the solution at a constant temperature; packing the particles in a vacuum sealing bag, performing gelation treatment by adopting a high hydrostatic pressure technology, and performing ultrasonic treatment to obtain the Arabic gum nano particles. Adding AM and distilled water, and homogenizing the mixture with a high-speed homogenizer; adding a photoinitiator azodiisobutyl imidazoline hydrochloride (VA-044) and a thermal initiator Ceric Ammonium Nitrate (CAN), sealing by nitrogen gas for oxygen displacement, placing the reactor into a transparent constant temperature box, irradiating by using an ultraviolet lamp, initiating polymerization reaction by adopting a photo-thermal synergistic initiation mode, curing and purifying to obtain the gum arabic high polymer synthesized by the composite initiation system. The obtained high polymer of the Arabic gum has high conversion rate and is a high-efficiency polymer in water treatment application.)

1. A method for synthesizing Arabic gum high polymer by a composite initiation system is characterized in that Arabic gum and Acrylamide (AM) are used as raw materials; dissolving Arabic gum in distilled water to prepare a 10-15% aqueous solution, and adjusting the pH value of the solution under a constant temperature condition; and packaging the gum arabic nanoparticles by using a vacuum sealing bag, putting the vacuum sealing bag into a medium (water) of a 600-800 Mpa High Hydrostatic Pressure (HHP) equipment cylinder, carrying out gelation treatment on the gum arabic for 30-45 min by adopting a high hydrostatic pressure technology, and carrying out ultrasonic treatment for 1-3 min to obtain the gum arabic nanoparticles. Adding AM and distilled water into the obtained nano particles, wherein the mass ratio of the gum arabic to the AM is 1-1.5: 1, and homogenizing the mixture by using an ultra-high speed homogenizer with the rotating speed of 6000-8000 r/min to obtain a colloidal dispersion with the particle concentration of the gum arabic before gelation; adding 0.2-0.6% of azodiisobutyl imidazoline hydrochloride (VA-044) serving as a photoinitiator and Ceric Amine Nitrate (CAN) serving as a thermal initiator in a ratio of 1-1.5: 1, using nitrogen to drive oxygen, sealing, placing the reactor into a transparent constant temperature box at 40-60 ℃, using an ultraviolet lamp to irradiate, initiating polymerization reaction for 1-2 hours by adopting a photo-thermal synergistic initiation mode, curing and purifying to obtain the gum arabic high polymer synthesized by the composite initiation system.

2. The method for synthesizing the gum arabic polymer according to the composite initiation system of claim 1, wherein after the gum arabic is dissolved, the pH of the solution is adjusted to 6.5-7.5 at a constant temperature of 25-30 ℃.

3. The method for synthesizing the high polymer of gum arabic according to the composite initiation system of claim 1, wherein the mixture is homogenized for 3-5 min by the ultra-high speed homogenizer.

Technical Field

The invention belongs to the technical field of flocculating agents, and particularly relates to a method for synthesizing a gum arabic high polymer through a composite initiation system.

Background

The coagulation method has the characteristics of simplicity, practicability, economy and high efficiency, and is widely applied to water treatment. In a coagulation experiment, the flocculant plays a main role, is an indispensable chemical agent in domestic water and wastewater treatment, is an important environmental ecological material, and plays an important role in the fields of providing safe and sanitary domestic water for urban residents, treating water pollution and the like. It mainly plays the roles of adsorption and electric neutralization, double electric layer compression, adsorption, bridging and the like in the water treatment process. The flocculant mainly comprises an inorganic flocculant, an organic polymeric flocculant, a natural organic polymeric flocculant and a microbial flocculant.

Gum arabic is a natural polysaccharide and has good solubility, emulsifiability, stability, and environmental friendliness, and can be used in many industrial fields. In recent years, the gum arabic has attracted more attention in the field of environmental engineering, but the effect of the gum arabic in environmental pollution treatment is not very remarkable, and in order to improve the flocculation effect of the gum arabic, gum arabic molecules can be prepared into nanoparticles by a certain method and subjected to targeted modification so as to improve the physicochemical property of the gum arabic. Currently, there is less research on this aspect.

Chinese patent application No. CN201510001967.6 entitled "preparation method and application of nanoparticles with photothermal effect" discloses a method for preparing nanoparticles with significant photothermal effect by using genipin to initiate polymerization reaction of molecules with positive charges such as chitosan in reverse microemulsion, modifying the surface with PEG to enhance biocompatibility, and finally carrying photothermal conversion material under the action of positive and negative charges. The nanometer particle has strong photo-thermal killing ability, but the preparation process is complex, and the nanometer particle is polluted to a certain extent by adding the cross-linking agent.

Chinese patent application No. CN201810562808.7, entitled "preparation method of hollow acacia gum nanospheres", discloses a method for preparing short amylose of starch by using a biological enzyme method, adding acacia gum into the short amylose to wrap the short amylose to form starch nanoparticles, and performing enzymolysis on the starch by using alpha # amylase to obtain the hollow acacia gum nanospheres. The method has the advantages of low equipment requirement, mild reaction and the like, but the preparation process is more complicated, and the flocculation and sedimentation performance of the obtained product is not good, so that the treatment effect is not particularly ideal.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides the gum arabic high polymer synthesized by the composite initiation system, which has simple process and stable product performance.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

taking Arabic gum and Acrylamide (AM) as raw materials; dissolving Arabic gum in distilled water, preparing into water solution after completely dissolving, and adjusting the pH value of the solution under constant temperature; and packaging the gum arabic powder by using a vacuum sealing bag, putting the packaged gum arabic powder into a medium (water) of a High Hydrostatic Pressure (HHP) equipment cylinder, carrying out gelation treatment on the gum arabic by using a high hydrostatic pressure technology, and carrying out ultrasonic treatment to obtain the gum arabic nanoparticles. Adding AM and distilled water into the obtained nanoparticles, and homogenizing the mixture with a super-high speed homogenizer to obtain a colloidal dispersion with a particle concentration of the gum arabic concentration before gelation; adding a photoinitiator azodiisobutyl imidazoline hydrochloride (VA-044) and a thermal initiator ceric nitrate amine (CAN), using nitrogen to drive oxygen, sealing, placing the reactor into a transparent thermostat, using an ultraviolet lamp to irradiate, initiating polymerization reaction by adopting a photo-thermal synergistic initiation mode, curing and purifying to obtain the gum arabic high polymer synthesized by the composite initiation system.

The method specifically comprises the following steps:

1) and (2) placing the gum arabic into distilled water, preparing a 10-15% gum arabic aqueous solution after the gum arabic is completely dissolved, and adjusting the pH value of the solution under a constant temperature condition.

2) And packaging the solution by using a vacuum sealing bag, then placing the packaged solution into a medium (water) of a 600-800 Mpa High Hydrostatic Pressure (HHP) equipment cylinder, standing for a period of time, gelatinizing the Arabic gum by using a high hydrostatic pressure technology to obtain Arabic gum gel, and then performing ultrasonic treatment to obtain the Arabic gum nanoparticles. When the induction pressure is less than 600Mpa, it is insufficient to induce the gum arabic into a gel. When the pressure is higher than 800MPa, the molecular bond of the gum arabic is easily broken, and gelation cannot be achieved.

3) An appropriate amount of acrylamide and distilled water were added to the obtained nanoparticles, and the mixture was homogenized with a super high speed homogenizer to obtain a colloidal dispersion having a particle concentration of gum arabic before gelation. The mass ratio of the Arabic gum to the AM in the nanoparticles is 1-1.5: 1. When the ratio is less than 1:1, self-crosslinking between AM monomers is likely to occur, which is not favorable for grafting onto the gum arabic nanoparticles. When the ratio is higher than 1.5:1, the amount of nanoparticles is excessive, and the water solubility of the prepared polymer sample is extremely poor.

4) Adding 0.2-0.6% of azodiisobutyronidazoline hydrochloride (VA-044) serving as a photoinitiator and Ceric Amine Nitrate (CAN) serving as a thermal initiator in a ratio of 1-1.5: 1, and using nitrogen to drive oxygen. When the concentration of the initiator is lower than 0.2%, the decomposed free radicals are low in number and cannot activate reaction sites on acrylamide and nano particles, so that the probability of the active groups participating in the reaction is reduced, the ratio of the number of graft copolymerization products to the length of a molecular chain is reduced, and the viscosity of the whole reaction system is low. When the initiator concentration is higher than 0.6%, the viscosity of the reaction system reaches a certain threshold value, the solubility of the gel nanoparticles and the monomer in the reaction system is reduced, the grafting reaction does not take the dominant role any more, and the increase of the homopolymerization reaction causes the reduction of the product and the reduction of the molecular weight.

5) And sealing the reactor, putting the reactor into a transparent constant temperature box at 40-60 ℃, irradiating by using an ultraviolet lamp, initiating polymerization reaction by adopting a photo-thermal synergistic initiation mode, curing and purifying to obtain the gum arabic high polymer synthesized by a composite initiation system. At a constant temperature of 40 ℃, the monomer activity and the rate of radical movement and diffusion are low, and therefore the reaction rate is low. The AM molecules are unable to bind sufficiently to the active sites of the gum arabic nanoparticles. When the temperature exceeds 70 ℃, the active centers of the nanoparticles become very unstable and the heat released by the polymerization reaction cannot be dissipated in time, so that chain transfer and chain termination occur, resulting in a decrease in grafting efficiency.

Wherein: in the step 1), the pH value should be adjusted to 6.5-7.5 under the constant temperature condition of 25-30 ℃.

The Arabic gum is a natural high molecular material and is widely distributed in nature. Consists of polysaccharide and protein structure with high relative molecular mass, and the molecular weight is different from hundreds of thousands to millions; it is widely distributed in nature, and has good adsorbability, low toxicity and environmental friendliness.

In the step 2), the gelling time is 30-45 min, and the ultrasonic treatment time is 1-3 min. When the time is less than 30min, the polycondensation reaction is incomplete and the gum arabic cannot be completely polycondensed into a gel. After 45min, gelation was completed, and the increase of time was almost not affected.

The homogenization time in the step 3) is 3-5 min, and the rotating speed is 6000-8000 r/min. When the rotation speed exceeds 8000r/min, the base state molecules, atoms and the like are easily dissociated gradually, and the number of active groups is gradually reduced.

In the step 5), the time of photo-thermal synergistic initiation is 1-2 h. The residual free radicals are not completely consumed until the polymerization time is 1 hour, the grafting efficiency is not too high, and after the polymerization time reaches 2 hours, the polymerization reaction between the monomers is completed, and the grafting efficiency is hardly affected by continuously increasing the temperature.

Compared with the prior art, the invention has the following beneficial effects:

1. the preparation method has the advantages of stable reaction, easy control and less side reaction, and the prepared gum arabic polymer synthesized by the composite initiation system has high molecular weight and good water solubility.

2. The invention adopts the method of preparing the Arabic gum into the nano particles and then carries out graft copolymerization with the monomer acrylamide, thereby greatly improving the removal rate of the soluble organic matters, and the removal rate is stabilized at more than 90 percent.

3. Compared with other high polymers, the gum arabic high polymer synthesized by the composite initiation system has higher conversion rate, is more beneficial to the sedimentation of flocs in the flocculation process, can be used for treating soluble organic matters and oily wastewater, and has remarkably enhanced water treatment performances such as pH application range, complexing capacity, salt resistance and the like. Therefore, the gum arabic high polymer synthesized by the composite initiation system has good social and economic benefits in practical application.

Detailed Description

The present invention will be described in further detail with reference to specific examples, wherein the raw materials used are common commercial products unless otherwise specified.