PEVA

TPU is a block copolymer consisting of alternating sequences of hard and soft segments or domains formed by the reaction of (1) diisocyanates with short-chain diols (so-called chain extenders) and (2) diisocyanates with long-chain diols. By varying the ratio, structure and/or molecular weight of the reaction compounds, an enormous variety of different TPU can be produced. This allows urethane chemists to fine-tune the polymer's structure to the desired final properties of the material.

Properties of commercially available TPU include:

• high abrasion resistance
• low-temperature performance
• high shear strength
• high elasticity
• transparency
• oil and grease resistance
  The currently available TPUs can be divided mainly in two groups, based on soft segment chemistry:
• polyester-based TPUs (mainly derived from adipic acid esters)
• polyether-based TPUs (mainly based on tetrahydrofuran (THF) ethers).

Net mesh is kind of common fabric, most of the sports shoes would like to be made of this kind of material, with some special points:

very cheap, comparing with other fabric, net mesh is very cheap;

mature technology means customer can find enough options on market;

breathable design

can be applied with several craft.

Lycra is a registered brand name for a polyurethane-based synthetic fiber that's also called spandex or elastane. The DuPont Company first developed Lycra in 1958 to replace latex rubber as a stretching agent in clothes. It's also prized for its strength and durability. Though you may think of shiny leotards and biking shorts when you think of Lycra, the elastic fabric is present in many garments.

Lycra can be mixed with cotton, and very well to be applied for clothes and shoes, as its outstanding performance such as fast dry, comfortable…

It is soft and can be stretched, although it is expensive, people like using it to make better products.

ETC fabric is not very common on market, but we should introduce it briefly here, as it is very excellent. ETC fabric is very expensive, more than 6 times than other common ones, but its performance is obvious. 

Anti-bacterial is one shining point of this fabric, it is not like other fabric has to be processed and then possese the the function, ETC fabric owns this function without any processing. 

Lower friction, as we know friction can lead heat, that why we feel hot when wearing some shoe insoles, that's because of heat. With low friction, ETC fabric could bring you cool feeling.

Breathble and fast dry. 

This kind of material was named very good, but it is not as good as other foam materials like ORTHOLITE or PORON, just because it is made with some kind of new raw materials mixed with recycled materials and compress to a certain stiffness materials. 

But this kind materials is also very breathable and sold with very competitive prices, so that we can use them for some developing market. 

Most of this kind material can not be as soft and strong as new materials, it is harder. 

What is aerogel
Aerogel is a special gel that replaces the liquid in the gel with gas without essentially changing the network structure or volume of the gel itself. one of the solid materials. It is also sometimes called "solid smoke" or "frozen smoke" because of its translucent color and ultra-light weight. Aerogels (aerogels) and dry gels (xerogels) are not the same concept. Wet gels are aerogels obtained by supercritical drying, and dry gels are obtained by atmospheric drying. Strictly speaking, aerogels should be bulk structures, while xerogels are generally powders or granules.​​
Due to its cumbersome and lengthy preparation process, high price and brittleness, etc., it has not attracted the attention of the industry for a long time. It was not until the advent of supercritical drying that aerogels caught the attention of researchers. The supercritical drying method can quickly and mass produce aerogel materials with precise size, arbitrary shape and complete structure. This new material looks fragile, but it is actually very strong and durable. Aerogels of different compositions can withstand different temperatures. Common silica aerogels can be used in the range of absolute zero to 650 °C. Some types of aerogels The glue can withstand high temperature up to 1400 ℃. It is gratifying that, unlike other new materials, the industrialization level of aerogel materials in my country is almost synchronized with the world, and it shows a good trend of catching up and surpassing. The first commercial aerogel company in my country was established in 2004.
Aerogels can be divided into three categories according to their components: inorganic aerogels, organic aerogels and composite aerogels. The most typical and most studied aerogels are single-component SiO2 aerogels and carbon aerogels (organic aerogels).​​

Characteristics of Aerogels
1. The porosity is very high, up to 99.8%; scientists say that because it has millions of pores and wrinkles, if you take 1 cubic centimeter of aerogel apart, it will fill a football field. big place. Its tiny pores not only trap pollutants like a sponge, but also act as air pockets. The researchers believe that some forms of aerogels made of platinum could be used to accelerate hydrolysis and hydrogen production. In this way, aerogels can be used to produce hydrogen-based fuels.
2. Nano-scale holes and three-dimensional nano-framework particles;
3. High specific surface area;
4. Low density;
5. The unique structure of aerogel determines its extremely low thermal conductivity, which can be as low as 0.013W/(m·K) at room temperature, which is lower than the thermal conductivity of air.

Each step you take involves a complex network of bones, muscles, tendons, and ligaments. This, combined with all of the weight they carry, explains why feet can have problems. To keep your feet healthy

• Examine your feet regularly
• Wear comfortable shoes that fit
• Wash your feet daily with soap and lukewarm water
• Trim your toenails straight across and not too short

Your foot health can be a clue to your overall health. For example, joint stiffness could mean arthritis. Tingling or numbness could be a sign of diabetes. Swelling might indicate kidney disease, heart disease, or high blood pressure.

Good foot care and regular foot checks are an important part of your health care. If you have foot problems, be sure to talk to your doctor.

Athlete's foot is a common infection caused by a fungus. It most often affects the space between the toes. Symptoms include itching, burning, and cracked, scaly skin between your toes.

You can get athlete's foot from damp surfaces, such as showers, swimming pools, and locker room floors. To prevent it

• Keep your feet clean, dry, and cool
• Wear clean socks
• Don't walk barefoot in public areas
• Wear flip-flops in locker room showers
• Keep your toenails clean and clipped short

Treatments include over-the-counter antifungal creams for most cases and prescription medicines for more serious infections. These usually clear up the infection, but it can come back.

Children’s feet are not the same as adults’ feet. Babies' and toddlers' feet are soft and pliable because the bones are not yet completely formed. This means their feet can be more easily damaged than the feet of older children e.g. by shoes that are too tight. Here are some tips for taking care of your child’s feet.

Shoes and socks

Toddlers do not need shoes indoors when they first start to walk. Letting them go barefoot or wearing socks alone helps their feet   grow normally and encourages their toes to develop a grasping action.

• Feet grow rapidly during childhood. Check that your child’s shoes fit properly every one to 3 months up to the age of 3 years, every 4 months between 3 and 5 years and every 6 months for children aged over 5.
• Make sure children wear fresh cotton socks daily and that they air their shoes overnight — this can help reduce skin problems.

• When choosing shoes for children, there should be about 1 cm ‘growing room’ between the longest toe and the end of the shoe. The shoe should also fit the foot’s natural shape, especially around the toes.

• Always have both of your child’s feet measured for length and width. Note that a child's left and right foot are unlikely to be exactly the same size.

• Never "hand down" shoes from one child to another.

• Uneven wear and tear on the heel of a shoe may indicate a foot problem that should be checked with a doctor or podiatrist.

Walking problems

• Flat feet are common in children, but are not necessarily a problem. Arch development will likely stabilise by the age of 6 or 7 years. However, take your child to a doctor or podiatrist if flat feet are causing pain or affecting your child’s walking or other activities.

• Most toddlers who walk with their feet pointed inwards (in-toeing or "pigeon toes") or with their feet pointed outwards (out-toeing) and those who appear to have bow legs, will be walking normally by the time they are 2. Take your child to a doctor or podiatrist if these walking patterns persist beyond the age of 2 or you are worried.

• Children walking on their toes can also be just a phase, but the Australasian Podiatry Council says it is "not normal" and recommends review by a podiatrist.

• Knock knees are normal in children aged 2 to 7 years. If the condition causes the foot to roll or be painful, orthoses (orthotics) may be advised.

• Signs that your child may have a problem needing investigation include frequent tripping and falling, withdrawing from sport and recreation, or lagging well behind other children during sport and play.