GATE Overflow for GATE XE - Recent questions in Polymer Blends and Composites

GATE XE 2025 | Question: 126

Sun, 04 May 2025 19:04:41 +0000

The crystallization of a polymer can only proceed in a temperature range limited to glass transition temperature ( $T_{g}$ ) on the lower side, and the equilibrium melting point $\left(T_{m}^{o}\right)$ on the higher side. Around $T_{g}$, the mobility of the polymer chains is lower, while in the proximity of $T_{m}^{o}$, crystal nucleation is inhibited.

In a miscible polymer blend with only one component being crystalline, which option(s) correctly match(es) the Temperature conditions with Events?

$$\begin{array}{|l|l|l|l|} \hline & \textbf{Temperature conditions} & & \textbf{Events} \\ \hline P & \text{The } T_{g} \text{ of the amorphous} & 1 & \text{The temperature range over} \\ & \text{component is lower than } \\ & \text{which crystallization can occur} \\ & \text{the crystallizable one} && \text{the crystallizable onebecomes smaller} \\ \hline Q & \text{The } T_{g} \text{ of the amorphous} & 2 & \text{Crystallization is inhibited} \\ & \text{component is higher than} \\ & \text{the crystallizable one} \\ \hline R & \text{The blend } T_{g} \text{ is higher than the} & 3 & \text{The crystallization envelope} \\ & (T_{m}^{o} \text{ of the crystalisable one} && (T_{m}^{o}-T_{g}) is widened \\ \hline & & 4 & \text{Crystallization is favored} \\
\hline \end{array}$$

$\mathrm{P}-3 ; \mathrm{Q}-2 ; \mathrm{R}-4$
$\mathrm{P}-3 ; \mathrm{Q}-1 ; \mathrm{R}-2$
$\mathrm{P}-4 ; \mathrm{Q}-1 ; \mathrm{R}-3$
$\mathrm{P}-4 ; \mathrm{Q}-1 ; \mathrm{R}-2$

GATE XE 2024 | Question: 104

Sun, 21 Jul 2024 16:41:19 +0000

A suitable physical compatibilizer of a binary blend of poly(ethylene) and poly$\text{(propylene)}$ is __________.

poly$\text{(caprolactam)}$
poly$\text{(lactic acid)}$
poly$\text{(ethylene-block-propylene)}$
poly$\text{(carbonate)}$

GATE XE 2024 | Question: 115

Sun, 21 Jul 2024 16:41:09 +0000

The glass transition temperature $\text{( $T_{g}$ )}$ of poly$\text{(2,6-dimethyl-p-phenylene oxide) (PPO)}$ is $206.8^{\circ} \mathrm{C}$ and the $T_{g}$ of poly(styrene) (PS) is $90^{\circ} \mathrm{C}$. The $T_{g}$ of a $50 / 50$ (wt/wt) miscible blend of $\mathrm{PPO} / \mathrm{PS}$ is __________ ${ }^{\circ} \mathrm{C}$ $\text{(rounded off to the nearest integer)}$.

GATE XE 2023 | Question: 103

Wed, 14 Feb 2024 18:08:44 +0000

\begin{tabular}{l|l}
Q. 113 & \begin{tabular}{l}
Among the options given, choose the most suitable compatibilizer for blending \\
Polyvinylidene fluoride (PVDF) and Acrylonitrile butadiene styrene (ABS).
\end{tabular} \\
\hline

& Styrene-acrylonitrile (SAN) \\
\hline
& Polybutadiene (PB) \\
\hline
& Polymethyl methacrylate (PMMA) \\
& Nylon 6
\end{tabular}