Factors Causing Rubber Aging in Ozone Aging Test Chamber

Due to the strong oxidizing effect of ozone, it can accelerate the aging of rubber and metals; Therefore, what the rubber industry absolutely cannot lack is an ozone aging test chamber, which simulates and strengthens the ozone conditions in the atmosphere, and is used to test the ozone aging resistance test performance of products. It can be divided into static and dynamic types according to customer requirements.

Ozone (O3), also known as superoxide, is a allotropy of oxygen (O2), which mainly exists in the lower ozone layer of the stratosphere 20-35 kilometers away from the earth’s surface. At normal temperature, it is a kind of light blue gas with a special odor; It is a harmful gas with a concentration of 6.25 × At 10-6mol/L (0.3mg/L), there is a sensation of irritation to the eyes, nose, and throat; Concentration (6.25-62.5) × At 10-5 mol/L (3-30mg/L), symptoms such as headache and local respiratory paralysis may occur; Ozone concentration is 3.125 × 10 -4 ～ 1.25 × When it is 10-3 mol/L (15-60mg/L), it is harmful to human health.

The air circulation device adopts a built-in circulating air duct, and the test airflow is evenly parallel to the surface of the specimen from top to bottom; The electromagnetic air pump provides high-quality air source, oil-free drying, ensuring the long-term reliability of the air circuit system; The instrument for measuring ozone has stable performance, automatic zero adjustment control, long service life of ozone free cold light source ultraviolet lamp, and high accuracy.

The Bill Lambert digital system measurement software is accurate and reliable; The integrated ozone concentration, temperature and humidity controller (the setting mode is light touch button type) is adopted, with high integration, good reliability, LED display, display resolution temperature (0.1 ℃), humidity (0.1% RH), ozone concentration (1 pphm), PID set value control, and convenient operation;

External isolation type, all stainless steel boiler type shallow surface evaporative humidifier; Using evaporator coil dehumidification method; The humidification water supply adopts automatic control and can recover residual water, saving water and reducing consumption; In addition, the ozone aging test chamber also has power overload and short circuit protection; Control circuit overload, short circuit protection, and grounding protection; Over temperature protection, alarm sound prompt, and water shortage protection; Having these protection systems can be more secure and reassuring in use.

What factors determine the cost-effectiveness of ozone aging test chambers?
1. The selection of control instruments is like the host of a computer, the human brain, which is a command center and the core component of the entire equipment. Therefore, the selection of control instruments is particularly important; The editor suggests choosing a touch screen controller, which has the advantages of high efficiency in controlling temperature and ozone, precise control, short self tuning time, and reliability compared to ordinary controllers;

2. sample fixtures, as mentioned earlier, can be divided into static and dynamic types according to customer requirements. Static: Place the test sample on the sample rack for direct testing; Dynamic: The sample is clamped on the dynamic fixture of the equipment to observe the aging situation under the dual effects of mechanical fatigue and ozone accelerated aging;

3. environmental temperatures, selected as needed. Some industry products require testing at temperatures below zero, some at room temperature, and some at high temperatures; Users should first understand the temperature at which their products need to be tested, as room temperature testing is commonly used.

The qualifications of the 4 manufacturers are not only sufficient for customers to purchase equipment, but also for services and technical support. Therefore, in order to ensure normal use and service guarantee in the future, it is necessary to choose a strong manufacturer.

Factors causing rubber aging in ozone aging test chamber:
1. Oxygen: Oxygen undergoes free radical chain reaction with rubber molecules in rubber, causing molecular chains to break or excessively crosslink, resulting in changes in rubber properties;

2. Heat: Increasing the temperature can cause thermal cracking or cross-linking of rubber. But the basic function of heat is still activation. Increasing the diffusion rate of oxygen and activating the oxidation reaction, thereby accelerating the oxidation reaction rate of rubber, is a common aging phenomenon – thermal oxygen aging;

3. Ozone: The chemical activity of ozone is much higher than that of oxygen, and it is more destructive. It also causes molecular chain breakage, but the effect of ozone on rubber varies depending on whether the rubber is deformed or not. When used as rubber for deformation (mainly unsaturated rubber), cracks appear in the direction of stress action, known as “ozone cracking”; When applied to deformed rubber, only an oxide film is formed on the surface without cracking;

4. Light: The shorter the light wave, the greater the energy; The destructive effect on rubber is caused by high-energy ultraviolet radiation. In addition to directly causing the breakage and cross-linking of rubber molecular chains, ultraviolet radiation also generates free radicals due to the absorption of light energy, triggering and accelerating the oxidation chain reaction process. Through external light, it plays a heating role; Another characteristic of light action (different from thermal action) is that it mainly grows on the surface of oak; A sample with a high adhesive content may exhibit network cracks on both sides, known as “outer layer cracking”;

5. Moisture: The function of moisture is twofold: rubber is prone to damage when exposed to humid air, rain, or soaked in water. This is due to the water-soluble substances and hydrophilic groups in rubber being extracted and dissolved by water, hydrolyzed, or absorbed. Especially under the alternating action of water immersion and atmospheric exposure, it will accelerate the damage of rubber. But in some cases, water does not have a destructive effect on rubber, and even has a delaying effect on aging;

6. Oil: If in long-term contact with oil media during use, oil can penetrate into the rubber and cause swelling, resulting in a decrease in the strength and other mechanical properties of the rubber. Oil can cause rubber to swell because after oil seeps into the rubber, molecules diffuse and the network structure of vulcanized rubber changes;

7. Mechanical stress: under the repeated action of mechanical stress, the rubber molecular chain will break and generate free spring, which will lead to oxidation chain reaction and form a force chemical process. Mechanical fracture of molecular chains and mechanical activation of oxidation processes. Which one has the advantage depends on the conditions they are in. In addition, it is easy to cause ozone cracking under stress;

8. Other factors that affect rubber include chemical media, variable valence metal ions, high-energy radiation, electricity, and biology;

Ozone test purpose:
Ozone Test Chamber (or called Ozone Aging Chamber and Ozone Aging Test Chamber) is design according to rubber being sensitive characteristic of to ozone, it simulate the environmental to accelerate the rubber aging process by ozone. It compared to different products(test sample) aging result each other according to the same ozone aging test conditions/standards, and get to comparable aging resistance performance.

OTC-015A_Ozone Test Chamber

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