Once being held back by a single piece of paper, how did China break the Western monopoly?

Paper - making technology is one of the four great ancient inventions of China that we are proud of.

However, China was once held back by Western countries because of "a piece of paper".

This piece of paper is aramid paper.

Aramid paper is not ordinary paper, but a polymer composite material.

Although it looks not much different from ordinary paper, it is one of the world's three high - performance fiber materials, with the full name of "polyarylamide fiber paper".

Aramid paper

To manufacture aramid paper, aramid polymer fibers need to be obtained first.

According to different molecular structures, the two most common types are aramid 1313 (PPTA) and aramid 1414 (PMTA).

The former is also called meta - aramid, and the latter is called para - aramid.

The two have similar structures, but different properties and uses.

Chemical structures of two types of aramid fibers

Aramid fibers do not exist in nature and can only be obtained through artificial synthesis to get this linear fiber. Different types of aramid fibers also have different production methods.

A relatively mature process is the low - temperature polymerization method.

This method consumes less organic solvents, the equipment required for the reaction is relatively easy to obtain, the operation steps are simple, the production efficiency is relatively high, and it has a wide range of applications.

A relatively new method is the interfacial polymerization method. This process is more complex, difficult to control, and has high requirements for equipment, so the investment is relatively large.

The low - temperature polymerization method is adopted by DuPont in the United States, while the interfacial polymerization method is used by Teijin in Japan.

In addition, there are also emulsion polymerization and gas - phase polymerization, but they are relatively rare.

Production process from aramid fibers to aramid paper

Aramid paper is actually a kind of non - woven fabric.

By mixing and dispersing aramid fibers, forming them by the wet method, and then using the hot - pressing process, aramid paper can be made.

Since its birth, aramid paper has been regarded as an important milestone in materials science and is known as the "gold and jewelry in the field of materials".

Aramid paper inherits the advantages of aramid fibers. Its strength is five or six times that of steel wire, its toughness is twice that of steel wire, but its mass is only about one - fifth of that of steel wire.

Aramid paper also has very high chemical and physical stability. It is resistant to acid and alkali corrosion, flame - retardant and high - temperature resistant, crack - resistant and impact - resistant, wear - resistant with little deformation, has good flame - retardant and insulation properties, and has a long service life...

These excellent properties make aramid paper worthy of the name of "paper gold".

Aramid paper was first developed by the United States for military use during the Cold War.

In 1967, DuPont in the United States achieved the industrial production of the meta - aramid material Nomex. It mainly uses its flame - retardant and high - temperature - resistant properties for the insulation gaskets of military equipment.

In 1972, DuPont successfully industrialized the meta - aramid material. It mainly uses its super - strong crack - resistant and impact - resistant properties to produce defense equipment, which is the well - known Kevlar.

Currently, the bullet - proof vests and helmets used by the military of countries such as the United States and the United Kingdom are all made of aramid materials.

Compared with steel helmets, aramid helmets have better wave - absorbing performance, can withstand high and low temperatures and acid and alkali, are harder than steel, but only one - third of the weight.

Aramid helmet

This is of great help in protecting soldiers and improving the mobility of individual soldiers in combat.

The function of Kevlar is not only for individual protection but also for anti - rebound protection.

For example, the protective cover of the US M1 tank is made of a steel - aramid - steel composite material, which can resist anti - tank missiles with a diameter of up to 700mm.

In the aerospace field, aramid paper is also one of the most commonly used special materials.

Aramid paper can be made into a honeycomb network structure. Its composite material has strong wave - absorbing properties and can be used to make stealth technology materials, enabling aircraft to effectively avoid detection by enemy radars and improving the survival probability.

For example, the wing skin of the US Air Force's B - 2 stealth bomber uses aramid materials.

US B - 2 stealth bomber

During the process of returning to the Earth, aerospace vehicles will have intense friction with the atmosphere, bringing a high temperature of 1000°C. Few materials can withstand such high - temperature challenges.

Aramid paper, as a flame - retardant and heat - resistant material, becomes the best choice.

In addition, aramid paper is very light, which can greatly reduce the overall mass of spacecraft.

You know, in the design of spacecraft, for every kilogram of weight reduced, the manufacturing cost can be reduced by about 1 million US dollars. Aramid paper is simply perfect!

Recently, Elon Musk's SpaceX has been very successful in rocket recovery. The Falcon 9 rocket has been successfully launched and recovered 17 times.

Speaking of which, Musk should really thank the emergence of aramid paper.

Falcon 9 rocket being recovered on landing

In the civilian field, aramid paper has even more uses.

The fire - proof suits made of aramid paper can be used at a high temperature of 260°C for 100 hours, becoming the best protection for firefighters from high - temperature erosion.

The outer material of aramid paper can effectively reduce the energy consumption and noise of high - speed trains. It is also an important high - temperature insulation material inside high - speed trains.

Aramid paper is also widely favored in the construction industry, used for roof insulation, thermal insulation of steel - structure engineering walls, indoor thermal insulation and sound absorption.

Aramid paper is also widely used in the construction of boats and kayaks. Most high - performance kayaks for water sports are made of aramid fibers or a composite material of carbon fiber/aramid fibers.

The US Coast Guard replaced asbestos boards with the honeycomb - structured Nomex, reducing the weight of speedboats by more than 9 tons.

According to statistics, 7% - 8% of bullet - proof vests and helmets are made of aramid paper. Nearly 40% of aerospace materials and sports equipment materials involve aramid paper, and the usage ratio of aramid paper in tire skeleton materials and conveyor belt materials has also reached 20%.

From civilian to military use, from sports to building materials, aramid paper can be found in various fields.

Such an important military and civilian material, but China was long held back by developed countries.

In the 1960s, after DuPont in the United States successfully industrialized aramid fibers, it was in a world - leading position in new product development, production scale, and market share.

Under DuPont's overall advantage, aramid paper quickly developed second - and third - generation products with higher performance.

With the latest technology in hand, the US government included aramid paper in the embargo list against China for all sorts of strange reasons.

Later, even though the US slightly relaxed the restrictions, it was only limited to the lowest - quality first - generation products, which could not meet military needs at all and could only be used for civilian purposes.

What's even more abominable is that an A4 - sized piece of aramid paper with a cost of less than 20 yuan once had a monopoly price as high as 2,800 yuan.

The US blockade once put China in a passive situation of "having no paper to use".

Aramid paper restricted the development of multiple fields in China and even became a bottleneck affecting China's aerospace and information technology.

Fortunately, the country had long realized this problem.

In 1972, China began to develop aramid fiber technology. It not only provided substantial funding for scientific research projects but also gave policy support to enterprises many times.

However, due to the lack of technical personnel and core technology, the development path has always been bumpy.

At the critical moment of solving the "bottleneck" technology, we have to mention two scientists.

The first to make a breakthrough was Professor Zhang Meiyun from Shaanxi University of Science and Technology, known as the "modern Cai Lun".

Her team has been deeply involved in high - performance aramid fibers and paper - based functional materials for nearly 40 years. They have published more than 200 high - level academic papers and obtained more than 40 national invention patents, ultimately laying a solid foundation for the emergence of aramid paper in China.

In 2007, China's domestic aramid paper entered the international market, breaking DuPont's monopoly.

Professor Zhang Meiyun

Professor Zhang Meiyun achieved catch - up, while Professor Hu Jian from South China University of Technology completed the overtaking.

In 2008, with the support of South China University of Technology, Professor Hu Jian formed a team. The next year, they began to tackle the research on the new - generation aramid paper technology.

In 2016, CRRC signed a cooperation agreement with South China University of Technology to jointly develop special - shaped parts such as aramid paper honeycombs.

In 2018, the domestic aramid paper developed by Professor Hu Jian's team was officially launched.

Aramid paper honeycomb

The new - generation domestic aramid paper completely surpasses the first two generations of products of DuPont in the United States and is comparable to DuPont's third - generation products. Its performance in terms of hardness, flexibility, and weight has doubled compared with the first - generation aramid paper.

China has officially broken the more than 50 - year aramid paper technology barrier of Western technological powers.

From then on, China has aramid paper technology comparable to that of American and Japanese enterprises and has thus become the fifth country, after the United States, the Netherlands, Japan, and Russia, capable of independently researching and producing aramid paper.

The well - known Tiangong - 2, Harmony Express high - speed train, and the domestic large - aircraft C919... all use ar