Chain extender is a kind of material which can expand the molecular chain and increase the

molecular weight by reacting with the functional group on the linear polymer chain.

Commonly used to improve the mechanical properties and processing properties of

polyurethane, polyester, nylon and other products.

Epoxy chain extender is a chain extender containing glycidyl methacrylate (GMA) .

Commonly used epoxy chain extenders include styrene-glycidyl methacrylate, which has

good thermal stability and can undergo ring-opening chemical reaction with PA6, rather than

pure physical mixing. It can also be used in waste PET recycling and other aspects. The

function of epoxy chain extenders in modified nylon is as follows:

1. Effect on molecular weight and intrinsic viscosity

Epoxy chain extenders can react with the end amino group and the end carboxyl group of

PA6, and then improve the molecular weight of PA6. However, gelation may occur during

the chain extension reaction, so it is necessary to control appropriate conditions, especially

temperature and screw speed, to prevent cross-linking in reactive extrusion.

The intrinsic viscosity of PA6 increased rapidly with the increase of the amount of chain

extender. When the content of chain extender increased to a certain mass fraction, the

intrinsic viscosity of PA6 decreased slightly. This is because the terminal group of PA6 can

react quickly with the epoxy group in the chain extender due to the polarity and hydrogen

bond. When the amount of chain extender is moderate, the proportion of long chain

molecules in the system increases and the viscosity increases accordingly;

However, as the reaction proceeds, the end group content of PA6 decreases, and the collision

probability at the end of the molecular chain is greatly reduced due to the influence of

thermal diffusion and the length of the molecular chain, in addition, too much chain extender

may lead to a small amount of gel in the system, which leads to a decrease in chain extension

efficiency and PA6 intrinsic viscosity.

2. Effect on mechanical properties

The relative molecular mass of PA6 was increased after chain extension with epoxy chain

extender, The toughness of the material can be effectively improved by decreasing

crystallinity and grain size.In addition, with the increase of the length of the molecular chain,

the entanglement between the chains increases, and the molecular chain is difficult to slip. In

this way, the impact energy can be absorbed by changing the configuration of the molecular

chain when it is impacted by the outside world. But when the mass fraction of chain extender

exceeds a certain proportion, all mechanical properties are reduced./n

3. Effect on rheological properties

The melt flow rate (MFR) decreased significantly with the increase of epoxy chain extender,

indicating that the epoxy chain extender and PA6 had an effective chain extension reaction.

With the increase of the amount of chain extender, the equilibrium torque increased firstly

and then decreased, because the relative molecular weight of PA6 after chain extension

increased, the entanglements in the molecular chain increased, and the melt viscosity also

increased, thus the equilibrium torque increased.

With the passage of time, the PA6 pellet softened, was compacted and melted gradually, the

resistance of the rotor decreased, and the torque also decreased.

Qingdao Sainuo Chemical Co.,Ltd. We are manufacturer for PE wax, PP wax,

OPEwax,EVAwax, PEMA, EBS,Zinc/Calcium Stearate…. Our products have passed

theREACH, ROHS, PAHS, FDA testing.

Sainuo rest assured wax, welcome your inquiry!

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