Toughening and Strengthening Mechanism of Calcium Carbonate Filler and Analysis of Modification Application of Composite Coupling Agent

The use of calcium carbonate as a toughening particle to improve the impact toughness of polymer materials is a mature polymer material modification technology. The toughening effect of calcium carbonate on plastics depends on the interfacial bonding strength between calcium carbonate and plastics. The traditional calcium carbonate surface treatment uses various acid ester coupling agents, fatty acid salts and grafts, etc., and the impact toughness of the composite material is not increased much. Therefore, the focus of research on composite interface modification is to develop composite coupling agents. A new type of composite coupling agent. After the interface enhancer is combined with the coupling agent, the surface of the calcium carbonate is treated to improve the bonding strength between the calcium carbonate and the polyolefin two-phase interface, thereby improving the compatibility between the polyolefin resin and the inorganic rigid particles, and The desired state of the inorganic particle coating layer is obtained to increase the impact strength of the composite material.

The toughening and strengthening mechanism of calcium carbonate is:

1. When deformed by external force, due to the presence of carbon-calcium particles, a stress concentration effect is generated, which causes the yielding of the poly-base resin olefin around it. The yield of this matrix will absorb a large amount of impact energy, resulting in Tseng effect;

2. When the crack encounters the calcium carbonate particles, the secondary priming effect of the binding-climbing-stranding-cracking will occur, causing the crack to expand;

3. Part of the two-phase interface is forced to form a cavity, so that the crack is passivated and does not develop into destructive cracking. The toughening effect from calcium carbonate depends on the bonding strength of the two-phase interface between polyethylene and the electrodeless filler.

Surface composite activation mechanism of calcium carbonate

Based on the toughening mechanism of calcium carbonate, increasing the bond and strength of the two phases is the key to improving the strength of the composite. When the polyolefin is filled with conventional calcium carbonate surface treatment technology, the two-phase interface structure is:

From the interface structure, the functional group of the coupling agent forms a chemical bond with the -OH of the surface of the calcium carbonate, so that the binding force between the calcium carbonate and the coupling agent is strong, when the length of the carbon chain end of the coupling agent is relatively high. Short, the long chain and the molecular chain of the polyolefin only have van der Waals force combined, which can not produce entanglement, so the strength is low. When subjected to an external force, the coupling agent and the polyolefin molecules are easily detached, so that the impact strength of the composite material is not greatly increased. After the introduction of a long carbon chain (100 or more carbon) interface enhancer having a polar group at the terminal group, the bonding strength of the coupling agent to the polyolefin molecule is greatly improved. When we extend the carbon chain length of the coupling agent, the long carbon chain can be entangled with the polyolefin molecular chain, and even partially form a eutectic, thereby playing a strong bridging effect, making the combination of calcium carbonate and polyolefin molecules more firm.

Effect of compound coupling agent content

The content of the composite coupling agent has little effect on the tensile strength of the composite, and has a certain influence on the impact strength. When the mass of the composite coupling agent is 1.8% of the mass of the calcium carbonate, the impact strength reaches a maximum value. The mass of the composite coupling agent is 1.8% of the mass of the calcium carbonate.

Effect of calcium carbonate content

Under the condition that the mass of the composite coupling agent is 1.8% of the mass of calcium carbonate, the influence of the content of calcium carbonate on the properties of the composite is investigated. The experimental results are shown in the following figure.

As can be seen from the above figure, as the calcium carbonate content increases, the tensile strength decreases, the impact strength first increases and then decreases, and when the mass of the calcium carbonate is 35% of the composite mass, the impact strength reaches a maximum. Therefore, it was determined that the optimum mass fraction of calcium carbonate in the composite material was 35%. The content of calcium carbonate has a great influence on the properties of the composite, which is related to the influence of calcium carbonate on the aggregation state and stress transmission of polyethylene. When the composite material is subjected to impact, the calcium carbonate particles not only serve to concentrate stress, cause silver streaks, but also act as stress conduction. When the content of calcium carbonate is increased, the stress conductivity between the calcium carbonate particles is improved, the impact energy is more uniformly diffused and consumed, and the impact property of the composite material is improved. However, when the content of calcium carbonate exceeds a certain amount, the pitch of the calcium carbonate particles is too small, and large cracks are likely to occur between the particles, resulting in a decrease in impact properties of the composite material.

Summary: The surface of the calcium carbonate is activated by a composite coupling agent composed of an interface reinforcing agent and a coupling agent, which greatly improves the interface bonding strength between the calcium carbonate and the polyolefin, thereby greatly improving the impact strength of the injection molded product. When the mass of the composite coupling agent is 1.8% of the mass of the calcium carbonate and the mass of the calcium carbonate is 35% of the mass of the composite, the impact strength of the composite material is ideal.

Effective Waste Water Decoloring Agent 

This product is a quaternary ammonium cationic polymer.

Product Name:
 Water Decoloring Agent
Solid Content:
50%~55%
Component:
Dicyandiamide-formaldehyde Resin
Other Names:
Decolorant;
Color Removal Agent;
Dicyandiamide-formaldehyde Resin Flocculant
Certificates:
ISO, SGS,BV
Service:
Trade Assurance protection for quality, shipment, payment

Specifications
Item
water decoloring agent 
Appearance
colorless or light-color sticky liquid
Dynamic viscosity (cps,20°C)
50-500
pH (30% water solution)
2.5~5.0
Solid content % ≥
50
Note:
our product can be made upon your special request.
Applications

1. It is mainly used for waste water treatment for textile, printing, dyeing, paper-making, mining, ink, and so on.
2. It can be used for 
color removal treatment for high-colority waste water from dyestuffs plants. It is suitable to treat waste water with activated, acidic and disperse dyestuffs.


Application Method


1.The product shall be diluted with 10-40 times water and then dosed into the waste water directly. After being mixed for several minutes, it can be precipitated or air-floated to become clear water.
2. The pH value of the waste water should be adjusted to 6-10 for better result.
3. When the colority and CODcr are relatively high, it can be used with the help of polyaluminum chloride, but not mixed together. In this way, the treatment cost can be lower. Whether polyaluminum chloride is used earlier or afterwards depends on the flocculation test and the treatment process.

Decolorizing Agent





Decolorizing Agent

Decolorizing Agent,Effective Decolorizing Agent,Waste Water Decoloring Agent,Water Decolorizing Agent

Shandong Tiancheng Chemical Co., Ltd. , https://www.akdchemical.nl