CN111285992A

CN111285992A - Method for preparing foamed cultivation substrate material by adopting bamboo liquefied resin

Info

Publication number: CN111285992A
Application number: CN202010187188.0A
Authority: CN
Inventors: 刘乐群; 刘震涛; 李国华
Original assignee: Zhejiang University of Technology ZJUT; Zhejiang Academy of Forestry
Current assignee: Zhejiang University of Technology ZJUT; Zhejiang Academy of Forestry
Priority date: 2020-03-17
Filing date: 2020-03-17
Publication date: 2020-06-16

Abstract

The invention designs a method for preparing a foamed cultivation substrate material by adopting bamboo liquefied resin. The method for preparing the cultivation substrate material is suitable for performance regulation and control of different plant cultivation environments and different plant growth requirements. The technical scheme is as follows: a method for preparing a foamed cultivation substrate material by adopting bamboo liquefied resin comprises the following steps: 1) adding a modifier into the liquefied bamboo resin, stirring, and modifying; 2) and sequentially pouring the surfactant, the foaming agent, the curing agent, MDI and the catalyst into the modified liquefied bamboo resin, uniformly stirring, pouring into a mold, standing for 1-5 hours, taking out, demolding and drying to obtain the modified liquefied bamboo resin.

Description

Method for preparing foamed cultivation substrate material by adopting bamboo liquefied resin

Technical Field

The invention designs a method for preparing a foamed cultivation substrate material by adopting bamboo liquefied resin.

Background

With the gradual improvement of the soilless culture technology of plants, the selection of culture mediums is more and more extensive. The culture medium can be divided into: organic matrix, inorganic matrix, mixed matrix. For example, organic substrates such as straws, wheat straw fibers, fly ash, municipal sludge and the like represented by organic raw materials have the characteristics of low price, wide sources, degradability, short production period and the like; inorganic substrates such as rock wool, waste colloidal particles, polyurethane bath and the like represented by inorganic raw materials have the characteristics of low nutrient content, poor water and fertilizer retention performance and the like; the mixed matrix prepared by mixing organic raw materials such as decomposed wood fiber, straw fiber, vinegar residue and chicken manure and inorganic raw materials such as furnace slag, gravel, perlite and the like has the characteristics of proper nutrients, improved water and fertilizer retention capacity, better air permeability and the like. However, the existing matrix material has the defects of poor physical and chemical property controllability, complex raw material source, unstable property, difficulty in industrial production and the like during manufacturing; with the increasing growth of plant flower culture, a green environment-friendly culture medium with stable and controllable properties is urgently needed to be found.

On the other hand, China is the country with the most bamboo processing enterprises in the world and the country with the largest bamboo forest area. In recent years, due to the characteristic of short growth cycle of bamboo wood, the bamboo wood processing relieves partial pressure of wood supply in China, and plays a great role in national economy. However, in the current bamboo processing and utilization, the utilization rate of the main material is low, the highest utilization rate is about 50 percent at present for manufacturing the bamboo mat plywood with the bamboo curtain, and most of bamboo processing residues are discarded. The method is not beneficial to the construction of the resource-saving, ecological, environment-friendly, efficient and sustainable bamboo processing industry. In addition, a large amount of small-diameter bamboos and residual bamboos of bamboo forests which cannot be well applied and processed also need to be fully utilized.

In order to fully utilize bamboo resources such as bamboo processing residues and small-diameter bamboos and improve the utilization rate of the resources, the invention researches more complete bamboo liquefaction related processes through early-stage deep research and can prepare bamboo liquefied resin with stable properties. However, how to use the bamboo liquefied resin to prepare the foamed matrix material which is suitable for plant growth, stable in performance and controllable in property still needs to further research and overcome the bottleneck existing in the prior art.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the background technology and provide a novel method for preparing a foamed cultivation substrate material by using bamboo liquefied product resin, and the method for preparing the cultivation substrate material meets the requirements of plant growth, has stable properties and is suitable for performance regulation and control of different plant cultivation environments and different plant growth requirements.

The invention is realized by the following technical scheme:

a method for preparing a foamed cultivation substrate material by adopting bamboo liquefied resin comprises the following steps:

1) adding a modifier into the liquefied bamboo resin, stirring, and modifying;

2) and sequentially pouring the surfactant, the foaming agent, the curing agent, MDI and the catalyst into the modified bamboo liquefied resin, uniformly stirring, pouring into a mould, standing for 1-5 hours, taking out, demoulding and drying to obtain the modified bamboo liquefied resin.

The curing agent is one or a mixture of more of acetic acid (acetic acid), phosphoric acid and p-toluenesulfonic acid (water) in any proportion, and the mass ratio of the curing agent to the bamboo liquefied resin is 6-15: 100.

The mass ratio of the MDI to the bamboo liquefied resin is 28-65: 100.

The surfactant is a mixture of one or more of emulsifier 10, Tween 80 and silicone oil in any proportion, and the mass ratio of the surfactant to the bamboo liquefied resin is 10-27: 100.

The foaming agent is one or a mixture of more of water, n-pentane and isopentane in any proportion, and the mass ratio of the foaming agent to the bamboo liquefied resin is 10-25: 100.

The catalyst is one or a mixture of more of triethylene diamine, stannous octoate and triethanolamine in any proportion, and the mass ratio of the catalyst to the bamboo liquefied resin is 0.5-2: 100.

The modifier is prepared from the following components in a mass ratio of 1: 1, the mass ratio of polyether polyol 330 and polyether polyol 4110 to the bamboo liquefied resin is 1-4: 100.

Before the foaming material is poured into the mould, 1-3 layers of mould release agent are plated on the mould.

The preparation process of the bamboo liquefied resin comprises the following steps: firstly, grinding bamboo wood into powder, and carrying out phenol alcohol liquefaction on the powder; and mixing the obtained liquefied product with sodium hydroxide, uniformly stirring, adding a formaldehyde solution, quickly heating to 90-100 ℃, reacting for 20-50 minutes, and cooling to room temperature.

The dosage of the formaldehyde and the sodium hydroxide is as follows: adding 42-63 parts by mass of 50-80% formaldehyde solution and 24-36 parts by mass of 20-45% sodium hydroxide solution into 100 parts by mass of bamboo powder.

The invention has the advantages that: by adopting the method, the waste bamboo resources can be prepared into the foaming matrix material which is useful for agriculture and forestry cultivation, and partial petrochemical materials can be effectively replaced, so that the waste of the bamboo resources is reduced, the utilization of the petrochemical resources is reduced, and the method is very beneficial to environmental protection and sustainable development. In addition, the material has a good cellular structure, and has good water absorption and water retention.

Drawings

FIG. 1 is a schematic diagram showing the effect of the resin ratio of the liquefied product of bamboo on the pH of the foaming matrix material.

Fig. 2 is a schematic diagram showing the effect of the resin ratio of the liquefied product of bamboo on the water retention and water absorption of the foamed matrix material.

FIG. 3 is a schematic diagram showing the effect of the resin ratio of the liquefied product of bamboo on the cells of the foamed substrate.

Detailed Description

The invention adopts the bamboo liquefied product resin to prepare the foaming culture substrate material, and the proportion of the bamboo liquefied resin has important influence on the foaming effect under the condition that the foaming reagent system and the capacity of the foaming mold are fixed. The pH of the culture medium directly influences the growth condition of plants, and if the medium is alkaline or too strong in acidity, the medium is not beneficial to the growth of plants; the foamed cultivation substrate can not be foamed and formed due to the fact that the proportion of the bamboo liquefied resin is too high or too low, and therefore the adjustment of the proportion of the bamboo liquefied resin is very important for the success of the test. In addition, the type of acid and the mixing ratio during the foaming process also have a very important influence on the test.

The preparation method of bamboo wood phenolic alcohol liquefaction adopts a Chinese patent 'preparation method of bamboo wood liquefaction product resin' (application number is 201110440838.9) applied by the inventor.

Example (b):

1.1 materials

Bamboo liquefied resin: the weight portion is 100, self-made;

the modifier is prepared from the following components in a mass ratio of 1: 1 polyether polyol 330 and polyether polyol 4110, in an amount of 1-4 parts by mass

Foaming agent: 10-25 parts of one or more of water, n-pentane and isopentane in any proportion.

The surfactant is one or a mixture of more of emulsifier 10, Tween 80 and silicone oil in any proportion, and the using amount is 10-27 parts by mass.

The catalyst is one or a mixture of more of triethylene diamine, stannous octoate and triethanolamine in any proportion, and the using amount is 0.5-2 parts by mass.

The curing agent is one or a mixture of acetic acid (acetic acid), phosphoric acid and p-toluenesulfonic acid (monohydrate) in any proportion, and 6-15 parts by mass.

The amount of MDI is 28-65 parts by mass.

The resin is self-made, and the medicines except MDI are analytically pure and purchased from Chengdu Kelong reagent factories.

The preparation method comprises the following steps:

1) adding a modifier into the liquefied bamboo resin, stirring, and modifying;

1.2 Main Equipment

GZX-9140MBE forced air drying cabinet (suzhou jiangdong precision instruments ltd); customizing a mould; an electronic balance (MAX 220 g); GZX-9140MBE forced air drying cabinet (limited department of precision instruments Jiandong, Suzhou); a glass rod; a beaker; plastic cup

1.3 methods

1.3.1 preparation of foamed cultivation substrate material: firstly, putting the resin into a plastic cup, adding a modifier, and stirring at a high speed for 20-30s to ensure that the resin is uniform; then adding a foaming agent and a surfactant, and adding a curing agent after the foaming agent, the surfactant and the resin are fully mixed; stirring until foams appear, adding MDI, mixing, pouring into a mold, standing for 1-3h (preferably 3h), demolding, taking out, and drying (preferably air drying for 6 h).

1.3.2 pH testing of the foamed matrix material: preparing a pH meter, a stirrer and removing CO₂Grinding the foaming matrix material into fine powder, placing 10g (to the accuracy of 0.01g) in a 50mL beaker, adding 25mL of CO-removed material₂Stirring with water for 1min, standing for 30min, and determining; then preparing a pH calibration solution to calibrate the pH; and after the sample is soaked and the pH meter is calibrated, directly measuring the solution by using the pH meter.

1.3.3 foamed matrix material Water absorption and Water Retention test:

water absorption: the sample should have a smooth and flat surface with dimensions of 150mm x 75 mm. And (3) placing the sample into a hydrostatic balance for testing, and calculating the water absorption according to the formula (1).

Water retention: taking out the sample which absorbs water from water, suspending the sample for 2min in a constant temperature environment of 25 ℃ without tension, then flatly paving the sample on a steel wire mesh, repeating the previous steps at intervals of 24h until the mass of the sample is almost unchanged, recording data, and calculating the water retention rate according to the formula (2).

In formulae (1) and (2): w_ab-water absorption; w_co-water retention; m is_dr-sample dry mass (g); m is_twAnd m_sw-mass after soaking in water (g) and mass after a period of drying (g).

1.3.4 foam substrate Material cell morphology Observation: before observation, the sample is placed on a sample table for gold plating, and after gold plating, the sample is placed under an accelerating voltage of 10kv for observation.

Example 1:

bamboo liquefied resin: 100 parts by mass (the same below)

Modifier 3.33 parts

Foaming reagent system: foaming agent: 25 parts of water, 1026.67 parts of surfactant emulsifier, 2 parts of catalyst stannous octoate, 15 parts of curing agent phosphoric acid and 64.67 parts of MDI.

Example 2:

bamboo liquefied resin: 100

2.5 portions of modifier

Foaming reagent system: foaming agent: 18.75 parts of n-pentane, 1020 parts of surfactant emulsifier, 2 parts of catalyst triethylene diamine, 11.25 parts of curing agent acetic acid and 48 parts of MDI.

Example 3:

bamboo liquefied resin: 100

2 portions of modifier

Foaming reagent system: 15 parts of foaming agent isopentane, 16 parts of surfactant silicone oil, 1 part of catalyst triethanolamine, 9 parts of curing agent p-toluenesulfonic acid (monohydrate) and 39 parts of MDI.

Example 4

Bamboo liquefied resin: 100

1.67 parts of modifier,

Foaming reagent system: foaming agent: 12.5 parts of water, 1013.33 parts of surfactant emulsifier, 1 part of catalyst triethylene diamine, 7.5 parts of curing agent phosphoric acid and 32.33 parts of MDI.

Example 5

Bamboo liquefied resin: 100

Modifier 1.43 parts

Foaming reagent system: foaming agent: 10.71 parts of isopentane, 8011.43 parts of surfactant Tween, 0.5 part of catalytic agent stannous octoate, 6.43 parts of curing agent acetic acid and 28.07 parts of MDI.

The preparation methods of the above examples are all as follows:

1) adding a modifier into the liquefied bamboo resin, stirring, and modifying;

2) and sequentially pouring the surfactant, the foaming agent, the curing agent, MDI and the catalyst into the modified bamboo liquefied resin, uniformly stirring, pouring into a mould, standing for 3 hours, taking out, demoulding and drying to obtain the modified bamboo liquefied resin.

Foaming agent system in the above examples: all refer to all other materials except the bamboo liquefied resin and the modifier adopted in the process of preparing the foamed cultivation substrate material, including: surfactants, blowing agents, curing agents, MDI, and catalysts.

2. Results and analysis

2.1 influence of the resin ratio of the liquefied product of bamboo on the pH and degree of foaming of the foamed matrix material

The bamboo liquefied resin is weakly alkaline at normal temperature, acid and alkali neutralization reaction can be generated by adding acid in the normal-temperature foaming process, a large amount of heat is generated in the process, so that the foaming agent is rapidly gasified, the system is pushed to foam, the heat value released by the reaction is directly influenced by the proportion of the bamboo liquefied resin and the proportion of the acid, and under the certain condition of the foaming agent, the higher the reaction heat value is, the more complete the gasification of the foaming agent is, the larger the foaming driving force is, and the better the foaming degree and the effect are in a certain range. When the proportion of the bamboo liquefied resin is higher, the proportion of the corresponding acid is reduced in the system, the trend is that the proportion of the bamboo liquefied resin is higher, the acidity of the cultivation substrate material is weaker, and the specific rule is shown in figure 1. In terms of degree of foaming, see table 2.

TABLE 2.1 degree of foaming of the foamed cultivation substrate material with different bamboo liquefied resin ratios

As can be seen from table 2.1 and fig. 1, as the ratio of the bamboo liquefied resin increases, the cell size decreases and the pH increases with the constant volume of the mold, and the comparison effect of example 2 (the mass ratio of the resin to the foaming agent system is 1: 1) is the best in consideration of the foaming degree, the cell uniformity, the cell size and the pH, so that the ratio is determined to be a good ratio.

2.2 influence of the resin ratio of the liquefied product of bamboo on the Water absorption and Water Retention of the foamed matrix Material

As a plant cultivation substrate, the water absorption rate and the water retention rate of the material have important influence on the growth and cultivation of plants, and the material with higher water absorption rate can absorb a large amount of water more quickly in the rain or irrigation process, so that the condition that water sources directly flow through the material is relieved; the method is applied to large-scale engineering, and can delay the occurrence of surface runoff phenomenon, reduce waterlogging or slow down the time of flood peak occurrence under the condition of rainstorm; the material with higher water retention rate can store water more easily, so the material with higher water retention rate can save water resources more, and is a material which is more in line with environmental protection and resource saving. As is apparent from fig. 2, the water absorption rate and the water retention rate of example 2 are the highest, the ratio of the water absorption rate to the water retention rate is also small, and the water absorption and retention performance is relatively high; example 1 the water retention was the lowest, although the water absorption was higher, because the material had a large void and a large degree of open pores, which resulted in poor water retention; in other proportion, the water absorption and water retention of the material are relatively small, but the ratio of the water absorption to the water retention is less than 3.0, and the material performance is general.

2.3 influence of the resin ratio of the liquefied product of bamboo on the cell structure of the foamed substrate material

As can be seen from the group of fig. 3, the cell structures of the materials of example 1 and example 2 are relatively large and the uniformity degree is good; the degree of cell uniformity of example 3 is typical; the uniformity of example 4 is better, and the cells are smaller; example 5 very few well formed cells were observed and the material exhibited poor cell size and cell uniformity. In conclusion, when the proportion of the foaming reagent system is low, the foaming process is insufficient, and the foam holes are smaller; when the proportion of the foaming agent system is large, the cell structure is influenced under the condition that the cells are extruded and deformed, and the water is not easily retained.

3. Conclusion

1) When the amount of the foaming agent used in example of the foaming agent is fixed to the foam volume, the ratio of the amount of the bamboo liquefied resin added to the foaming agent system in example 2 (1: 1), the foamed cultivation substrate material has better pH, water absorption rate, water retention rate, cell structure and other aspects, and the cultivation substrate material with better comprehensive performance can be prepared according to the proportion.

2) According to the tests, when the proportion of the resin is gradually increased, the pH value of the resin is also increased, the plant growth is not facilitated, and meanwhile, the proportion of the foaming reagent system is gradually reduced, so that insufficient foaming is caused, the cells are smaller, and the uniform degree of the cells is more difficult to control.

Claims

1. A method for preparing a foamed cultivation substrate material by adopting bamboo liquefied resin comprises the following steps:

1) adding a modifier into the liquefied bamboo resin, stirring, and modifying;

2) and sequentially pouring the surfactant, the foaming agent, the curing agent, MDI and the catalyst into the modified liquefied bamboo resin, uniformly stirring, pouring into a mold, standing for 1-5 hours, taking out, demolding and drying to obtain the modified liquefied bamboo resin.

2. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 1, is characterized in that: the curing agent is one or a mixture of more of acetic acid, phosphoric acid and p-toluenesulfonic acid (monohydrate) in any proportion, and the mass ratio of the curing agent to the bamboo liquefied resin is 6-15: 100.

3. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 2, is characterized in that: the mass ratio of the MDI to the bamboo liquefied resin is 28-65: 100.

4. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 3, is characterized in that: the surfactant is a mixture of one or more of emulsifier 10, Tween 80 and silicone oil in any proportion, and the mass ratio of the surfactant to the bamboo liquefied resin is 10-27: 100.

5. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 4, is characterized in that: the foaming agent is one or a mixture of more of water, n-pentane and isopentane in any proportion, and the mass ratio of the foaming agent to the bamboo liquefied resin is 10-25: 100.

6. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 5, is characterized in that: the catalyst is one or a mixture of more of triethylene diamine, stannous octoate and triethanolamine in any proportion, and the mass ratio of the catalyst to the bamboo liquefied resin is 0.5-2: 100.

7. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 6, is characterized in that: the modifier is prepared from the following components in a mass ratio of 1: the mass ratio of polyether polyol 330 and polyether polyol 4110 of 1 to the bamboo liquefied resin is 1-4: 100.

8. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 7, is characterized in that: before the foaming material is poured into the mould, 1-3 layers of mould release agent are plated on the mould.

9. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 8, is characterized in that: the preparation process of the bamboo liquefied resin comprises the following steps: firstly, grinding bamboo wood into powder, and carrying out phenol alcohol liquefaction on the powder; and mixing the obtained liquefied product with sodium hydroxide, uniformly stirring, adding a formaldehyde solution, quickly heating to 90-100 ℃, reacting for 20-50 minutes, and cooling to room temperature.

10. The method for preparing the foamed cultivation substrate material by adopting the bamboo liquefied resin as claimed in claim 9, is characterized in that: the dosage of the formaldehyde and the sodium hydroxide is as follows: adding 42-63 parts by mass of 50-80% formaldehyde solution and 24-36 parts by mass of 20-45% sodium hydroxide solution into 100 parts by mass of bamboo powder.