CN106480780B - A kind of paper making intensifier based on hemicellulose and preparation method and application - Google Patents

Abstract

The invention discloses a kind of paper making intensifiers based on hemicellulose and preparation method and application.This method includes the following steps：Xylan is dissolved in ultra-pure water, is dissolved by heating in water-bath, leads to nitrogen, adds in initiator, causes and adds in grafted monomers acrylamide after a certain period of time, product cooling, is washed with acetone after having reacted, and then vacuum drying obtains crude product.Dry crude product is put into acetic acid with being impregnated in ethylene glycol mixture repeatedly, then vacuum drying obtains the high xylan grafted polyacrylamide of purity.The xylan grafted polyacrylamide has both xylan and polyacrylamide performance, and price is less expensive, flocculability is good, effectively improves the paper performance of secondary stock.The preparation method of the present invention has technique characteristic easy to operate, environmental-friendly.

Description

A kind of hemicellulose-based papermaking strengthening agent and its preparation method and application

technical field

The invention relates to the field of papermaking strengthening agents, in particular to a hemicellulose-based papermaking strengthening agent and its preparation method and application.

Background technique

Due to the gradual depletion of fossil resources and the continuous deterioration of environmental problems. Agricultural and forestry biomass has the advantages of environmental friendliness, biodegradability, and short regeneration cycle. The production of high value-added chemicals from agricultural waste is considered to be one of the effective ways to solve environmental and energy problems.

Xylan-grafted polyacrylamide is a chemically modified derivative of xylan, which is obtained by high-temperature graft copolymerization of xylan and acrylamide. It has a strong flocculation effect, and polyacrylamide has amide groups, which can form hydrogen bonds with cellulose, which can effectively improve the performance of pulp, so it can be used in the paper industry. The xylan-grafted polyacrylamide prepared by the method has environmental friendliness and little environmental pollution.

In recent years, the deep processing of biomass has attracted the attention of many scientists, among which the graft copolymerization modification method of biomass is particularly attractive. Biomass graft copolymerization includes graft copolymerization of cellulose, graft copolymerization of hemicellulose, graft copolymerization of chitosan and so on. The biomass modified by graft copolymerization has the good characteristics of grafted monomers, which makes the application range of biomass wider and becomes a research hotspot at home and abroad. Using xylan-grafted acrylamide to replace the traditional paper-making strengthening agent greatly reduces the disadvantages of production cost and environmental pollution, and is technically and economically feasible.

Contents of the invention

In order to solve the above shortcomings and deficiencies of the prior art, the object of the present invention is to provide a hemicellulose-based paper-making strengthening agent and its preparation method and application. The xylan-grafted polyacrylamide has the properties of xylan and polyacrylamide, is relatively cheap, has good flocculation performance, and effectively improves the paper performance of waste paper pulp. The preparation method of the invention has the advantages of easy process operation and environmental friendliness.

The purpose of the present invention is achieved through the following technical solutions.

A preparation method of a hemicellulose-based papermaking reinforcing agent, comprising the steps of:

(1) Grafting and copolymerization of xylan: Weigh xylan powder and dissolve it in ultrapure water, heat and dissolve in a water bath, pass nitrogen to remove the air, add an initiator to initiate, then add acrylamide to obtain a reaction solution, and the reaction is completed The final product was cooled to room temperature, washed, and dried in a vacuum oven to obtain a crude product;

(2) Preparation of refined product: soak the crude product obtained in step (1) in a mixed solution of acetic acid and ethylene glycol, and then dry it in a vacuum oven to obtain a refined product, which is a hemicellulose-based papermaking strengthening agent.

Preferably, the temperature of the water bath in step (1) is 40°C to 80°C.

Preferably, the initiator in step (1) is potassium persulfate, and the mass ratio of initiator to xylan is 1:(2-13); the initiation time is 10 minutes. Further preferably, the amount of the initiator is 0.0003-0.0017 mol.

Preferably, the mass ratio of xylan powder to acrylamide in step (1) is 1: (1-4).

Further preferably, the xylan powder described in step (1) has a mass of 1 g.

Preferably, the concentration of acrylamide in the reaction solution obtained in step (1) is 0.176mol/L-1.057mol/L; more preferably, the concentration of acrylamide is 0.354mol/L.

Preferably, the reaction temperature of xylan and acrylamide in step (1) is 40°C-80°C, and the time is 2h-6h; more preferably, the reaction temperature is 60°C, and the reaction time is 4h. .

Preferably, the preparation of xylan-grafted polyacrylamide by modifying xylan described in step (1) is as follows: adding xylan into hot water at a temperature of 60°C, stirring and dissolving for 30 minutes, and then adding an initiator Potassium sulfate, add a certain amount of acrylamide after 10 minutes, and react at 60°C for 2h~6h, wherein the mass ratio of xylan:acrylamide is 1:(1~4).

Preferably, the volume ratio of acetic acid to ethylene glycol in the mixed solution of acetic acid and ethylene glycol in step (2) is 4:6˜8:2.

Preferably, the number of times of soaking in step (2) is 3 to 5 times, and the time of each soaking is 2 to 3 hours.

Preferably, the drying in step (1) and step (2) is drying at 40° C. to 80° C. for 12 to 24 hours.

The present invention also provides a hemicellulose-based paper-making strengthening agent prepared by the above-mentioned preparation method. The hemicellulose-based papermaking strengthening agent can be applied in the papermaking industry.

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

(1) The xylan-grafted polyacrylamide prepared by the present invention has the characteristics of polyacrylamide and the performance of xylan, and can be used as a papermaking strengthening agent in the papermaking industry.

(2) In the process of grafting polyacrylamide to xylan prepared by the present invention, the reaction conditions are mild, the operation is easy to control, and it is easy to realize industrialization.

Description of drawings

Fig. 1 is the infrared spectrum of xylan and xylan-grafted polyacrylamide in embodiment 1.

Detailed ways

The present invention will be further explained below in conjunction with the implementation, but the embodiments of the present invention are not limited thereto.

Example 1

(1) Weigh 1g of xylan powder and dissolve it in ultrapure water, heat and dissolve in a water bath at 60°C, blow nitrogen to remove the air, add 0.0003mol initiator potassium persulfate, add 1g of acrylamide monomer after 10min, Reaction at 60°C for 2h.

(2) The reaction product of step (1) is cooled to room temperature, washed with acetone, and filtered 3 times. After the filtered product is placed in a fume hood for 3 hours, it is placed in a vacuum drying oven and dried at 40° C. for 12 hours to obtain crude product.

(3) Put the dried thick product of step (2) into acetic acid and ethylene glycol mixed solution (the volume ratio of acetic acid and ethylene glycol is 4:6) and soak 3 times, each time for 2h, after placing in a fume hood for 3h, Put it in a vacuum drying oven and dry it at 60°C for 24 hours to obtain a refined product, that is, xylan grafted polyacrylamide.

The grafting rate of the obtained product was 27.02%. Add 0.054g of xylan grafted acrylamide with a mass fraction of 1% to the waste newsprint pulp with a pulp concentration of 0.5wt%, and place it in a constant temperature and humidity room for 24 hours through a sheet test. Finally, the strength of raw paper pulp is as follows: the burst index is 1.5Kpa·m2/g, the tear index is 6.02mN·m2/g, and the tensile strength is 1.21kN/m. Compared with the strength of raw paper pulp, its tensile strength has increased by 26.4%, the tear index has increased by 30.2%, the burst resistance has increased by 20.3%, and the number of folding endurance has increased significantly. There is an obvious improvement in the performance of the pulp, and it has great prospects in the application of the paper industry.

Example 2

(1) Weigh 1g of xylan powder and dissolve it in ultrapure water, heat and dissolve in a water bath at 60°C, blow nitrogen to remove the air, add 0.001mol initiator potassium persulfate, add 2g of acrylamide monomer after 10min, Reaction at 70°C for 4h.

(2) Cool the reaction product of step (1) to room temperature, wash and filter 3 times with acetone, place the filtered product in a fume hood for 3 hours, put it in a vacuum drying oven, and dry it at 60°C for 24 hours to obtain crude product.

(3) Soak the dried crude product in step (2) in the mixture of acetic acid and ethylene glycol (the volume ratio of acetic acid and ethylene glycol is 6:4) for 4 times, each time for 2.5 hours, and place it in a fume hood for 3 hours Finally, put it in a vacuum oven and dry it at 60°C for 24 hours to obtain a refined product, that is, xylan-grafted polyacrylamide.

The grafting ratio of the obtained product was 84.96%. Add 0.054g of xylan grafted acrylamide with a mass fraction of 1% to the waste newsprint pulp with a pulp concentration of 0.5wt%, and place it in a constant temperature and humidity room for 24 hours through the sheet test. Finally, the strength of raw paper pulp is as follows: the burst index is 1.5Kpa·m2/g, the tear index is 6.02mN·m2/g, and the tensile strength is 1.21kN/m. Compared with the strength of raw paper pulp, its tensile strength increased by 27.3%, tear index increased by 49.2%, burst resistance increased by 24.5%, and folding endurance times increased significantly. There is an obvious improvement in the performance of the pulp, and it has great prospects in the application of the paper industry.

Example 3

(1) Weigh 1g of xylan powder and dissolve it in ultrapure water, heat and dissolve in a water bath at 60°C, blow nitrogen to remove the air, add 0.0017mol initiator potassium persulfate, add 4g of acrylamide monomer after 10min, Reaction at 80°C for 6h.

(2) Cool the reaction product of step (1) to room temperature, wash and filter 3 times with acetone, place the filtered product in a fume hood for 3 hours, put it in a vacuum drying oven, and dry it at 60°C for 24 hours to obtain crude product.

(3) Soak the crude product dried in step (2) in the mixture of acetic acid and ethylene glycol (the volume ratio of acetic acid and ethylene glycol is 8:2) for 5 times, 3 hours each time, and place it in the fume hood for 3 hours , placed in a vacuum oven, and dried at 60° C. for 24 hours to obtain a refined product, xylan-grafted polyacrylamide.

The grafting rate of the obtained product was 35.44%. Add 0.054g of xylan grafted acrylamide with a mass fraction of 1% to the waste newsprint pulp with a pulp concentration of 0.5wt%, and place it in a constant temperature and humidity chamber for 24 hours through the sheet test. Finally, the strength of raw paper pulp is as follows: the burst index is 1.5Kpa·m2/g, the tear index is 6.02mN·m2/g, and the tensile strength is 1.21kN/m. Compared with the strength of raw paper pulp, its tensile strength increased by 31.4%, tear index increased by 24.9%, burst resistance increased by 23.3%, and the number of folding endurance increased significantly. There is an obvious improvement in the performance of the pulp, and it has great prospects in the application of the paper industry.

It can be seen from Figure 1 that both xylan and xylan-grafted polyacrylamide of Example 1 have a broad peak in the stretching vibration of the functional group O-H at 3600-3200 cm ^-1 ; There is one broad peak at 2800cm ^-1 ; the stretching vibration of carbohydrate C=O has one broad peak at 1665～1600cm ^-1 ; the stretching vibration of C－O has two broad peaks at 1200～1000cm ^-1 . Compared with the infrared spectrum of xylan, the infrared spectrum of xylan-grafted polyacrylamide has a more obvious absorption peak at 3600-3200 cm ^-1 , which is the mutual superposition of the absorption peaks of the stretching vibration of -OH and -NH ₂ And the absorption peak of the stretching vibration of -NH ₂ can only be seen as a shoulder due to the superposition of strong and broad hydroxyl absorption peaks. The absorption peaks of C-N appeared at 1100～1300cm ^-1 , these are the absorption peaks that polyacrylamide should have, and the infrared spectra of xylan and xylan-grafted polyacrylamide in other examples are consistent with Figure 1 , which shows that the xylan-grafted polyacrylamide prepared by the present invention has the characteristics of polyacrylamide and the performance of xylan, and can be used as a paper-making strengthening agent in the paper-making industry.

The elemental analysis of xylan and xylan-grafted polyacrylamide is shown in Table 1.

Table 1

It can be seen from Table 1 that the mass fraction of N in the xylan graft copolymer increases significantly, and it can be concluded that the graft copolymer increases the functional group of N, that is, the graft copolymer is grafted with PAM. And as the grafting rate increases, the N content continues to increase. The graft copolymer contains S because the initiator has not been completely removed.

Claims (9)

1. a kind of preparation method of the paper making intensifier based on hemicellulose, which is characterized in that include the following steps：

（1）Xylan graft copolymerization：It weighs xylan powder to be dissolved in ultra-pure water, be dissolved by heating in water-bath, lead to nitrogen row Fall air, add in initiator and cause, add acrylamide and obtain reaction solution, product is cooled to room temperature after having reacted, and is washed, true It is dry in empty drying box, obtain crude product；The temperature of the water-bath is 40 DEG C~80 DEG C；

（2）The preparation of smart product：By step（1）Gained crude product is put into acetic acid and is impregnated in ethylene glycol mixture, then is put into true It is dry in empty drying box, obtain the smart product i.e. paper making intensifier based on hemicellulose.

2. preparation method according to claim 1, which is characterized in that step（1）The initiator is potassium peroxydisulfate, is caused The mass ratio of agent and xylan powder is 1:(2~13)；The time of the initiation is 10min.

3. preparation method according to claim 1, which is characterized in that step（1）The xylan powder and acrylamide Mass ratio be 1：（1~4）；Acrylamide is in step（1）A concentration of 0.176mol/L~1.057 in gained reaction solution mol/L。

4. preparation method according to claim 1, which is characterized in that step（1）What middle xylan was reacted with acrylamide Temperature is 40 DEG C~80 DEG C, and the time is 2h~6h.

5. preparation method according to claim 1, which is characterized in that step（2）In the acetic acid and ethylene glycol mixture The volume ratio of acetic acid and ethylene glycol is 4:6~8:2.

6. preparation method according to claim 1, which is characterized in that step（2）The number of the immersion is 3~5 times, often The time of secondary immersion is 2~3h.

7. preparation method according to claim 1, which is characterized in that step（1）, step（2）The drying is 40^oC~ 80^oC dryings 12~for 24 hours.

8. a kind of paper making intensifier based on hemicellulose as made from claim 1-7 any one of them preparation methods.

9. a kind of paper making intensifier based on hemicellulose according to any one of claims 8 is applied in paper industry.