Выпишите конструкции в страдательном залоге из 4-го абзаца текста, определите их время. Текст: Thermoplastics are plastics able to melt. The thermoplastic materials are processed with heat. When enough heat is added to bring the temperature of the

Выпишите конструкции в страдательном залоге из 4-го абзаца
текста, определите их время.
Образец: is constructed – Present Simple Passive
1. In general, a composite consists of the matrix and the interface. By
carefully choosing the matrix, the reinforcement, and the manufacturing process
that brings them together, the engineers can tailor the properties to meet specific
requirements. Over the recent decades, many new composites have been
developed, some with very valuable properties.
2. Any material can serve as a matrix material for composite. However,
matrix materials are generally ceramics, metals, and polymers. There are several
different polymer matrices which can be utilised in composite materials. Among
the polymer matrix composites, thermoset matrix composites are more
predominant than thermoplastic composites. Though thermoset and
thermoplastics sound similar, they have different properties and applications.
Understanding the performance differences can help to make better decisions
and the product designs.
3. Thermosets are materials that undergo a chemical reaction or curing
and normally are transformed from liquid to a solid state. In its uncured form,
the material has molecules known as monomers. The addition of a second
material as a catalyst, and/or the presence of heat will initiate the chemical or
curing reaction. During this reaction, the molecules cross-link and form
significantly longer molecular chains and cross-link network, causing the
material to solidify. The change of the thermoset state is permanent and
irreversible. Subsequently, exposure to high heat after solidifying will cause the
material to degrade, not melt.
4. Thermoplastics are plastics able to melt. The thermoplastic materials
are processed with heat. When enough heat is added to bring the temperature of
the plastic above its melting point, the plastic melts or softens enough to be
processed. When the heat source is removed and the temperature of the plastic
drops below its melting point, the plastic solidifies back into a glasslike solid.
This process can be repeated, with the plastic melting and solidifying as the
temperature climbs above and drops below the melting temperature,
20 respectively. However, the material can be increasingly subject to deterioration
in its molten state, so there is a limit to the number of times that this
reprocessing can take place before the material properties begin to suffer.
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