Recent questions in Polymer Science and Engineering

​​​​​Which option(s) correctly match(es) the $\textbf{Class of additives}$ used during polymer compounding with the corresponding $\textbf{Chemicals}$?$$\begin{array}{|l|...

​​​In a set of copolymerization reactions, the following monomer reactivity ratios ($\textbf{r 1}$ and $\textbf{r 2}$) were found for different cases.$$\begin{array}{|c|c...

​​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 melt...

The heat of polymerization of ethylene is $25 \mathrm{kcal} / \mathrm{mol}$. The amount of heat generated during the polymerization of $5.6$ $\textsf{kg}$ polyethylene is...

The density of an amorphous polymer is $0.77 \mathrm{~g} \mathrm{~cm}^{-3}$ and that of its crystalline counterpart is $0.99 \mathrm{~g} \mathrm{~cm}^{-3}$. The density o...

Titration was used to determine the molar mass of two linear monodisperse polymers $\text{A}$ and $\text{B}$. Both the polymers possess the same repeat unit and contain a...

A unidirectional composite of a resin is prepared with continuous fibers, wherein the volume fraction of the fiber in the composite is $0.7$. Assume that the resin has a ...

A rubber contains $70 \mathrm{wt} \%$ butadiene (molar mass $=54 \mathrm{~g} / \mathrm{mol})$, $20 \: \mathrm{wt} \%$ isoprene (molar mass $=68 \mathrm{~g} / \mathrm{mol}...

​​​​Which of the following is the most suitable flexible packaging laminate for dry fruits?$\textsf{PET/LDPE}$$\textsf{PS/LDPE}$$\textsf{BOPP/LDPE}$$\textsf{Nylon/LDPE}$

In ball milling of ceramic powder, selection of grinding media depends on the __________ difference between grinding media and powder particles.thermal conductivitydielec...

Which of the following options is/are true for glass transition temperature $\mathrm{T}_{\mathrm{g}}$ ?Above $\mathrm{T}_{\mathrm{g}}$, glass transforms from an amorphous...

For chemical vapour deposition $\text{(CVD)}$ process, which of the following statements is/are correct?Target material is stripped off by the bombardment of positive ion...

Consider a unidirectionally aligned continuous glass fibre reinforced epoxy composite with $40$ vol. $\%$ reinforcement. The elastic modulus of the composite along the fi...

Phenol-formaldehyde resin is prepared bycondensation polymerizationcationic polymerizationanionic polymerizationring opening polymerization

Melting phenomenon in a semi-crystalline polymer is a __________ order phase transition.zerothfirstsecondthird

A certain polymer synthesized in the laboratory shows that all the chains have same number of repeat units $\text{(i.e., same degree of polymerization)}$. The relationshi...

Nitrile rubber is the copolymer ofstyrene and butadienestyrene and isoprenestyrene and acrylonitrilebutadiene and acrylonitrile

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

The 'die swell' phenomenon exhibited by a polymer melt is due toviscous deformationplastic deformationviscous and elastic deformationelastic recovery

Thermoforming operation of semi-crystalline polymers with glass transition temperature, $T_{g}$, and melting temperature, $T_{m}$, is carried out at a temperature $T$, in...

Feedstock recycling of poly$\text{(ethylene terephthalate)}$ is carried out byhydrogenationdehydrogenationhydrolysisozonation

Which of the following polymers is/are synthesized by ring opening polymerization?Poly$\text{(lactic acid)}$Poly$\text{( $\varepsilon$-caprolactone)}$Poly$\text{(styrene)...

The propagation step of a free radical copolymerization is represented by the following possible reaction steps:$\text{P1}$: $M_{1}^{*}+M_{1} \rightarrow M_{1}^{*}, \quad...

Match the following additives to their respective functions for poly$\text{(vinyl chloride)}$ compounding.AdditiveFunctionP. Dibutyltin maleate1. LubricantQ. Epoxydized s...

Match the following properties with their respective units.PropertyUnitP. Notched Izod impact strength$1 . \mathrm{Pa} \mathrm{s}$Q. Flexural strength$2 . \mathrm{J} \mat...

Melt flow index $\text{(MFI)}$ of a polymer depends on its molecular weight $(M W)$ and melt viscosity $(\eta)$. Select the correct relation(s) from the following.$\text{...

Biaxially oriented poly$\text{(propylene)}$ exhibits high clarity because layering of the crystalline structuresdecreases the variation in refractive index across the fil...

If a given poly(ethylene) sample with specific volume, $v=1.042 \times 10^{-3} \mathrm{~m}^{3} \mathrm{~kg}^{-1}$ shows:specific volume of the crystalline fraction, $v_{c...

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...

A unidirectional composite is prepared using $70 \%$ by volume of epoxy matrix and $30 \%$ by volume of carbon fibre. The elastic modulus of the epoxy matrix is $3.5$ GPa...

A monodisperse polymer sample of molecular weight $10,000 \mathrm{~g} \mathrm{~mol}^{-1}$ is mixed with another monodisperse sample of the same polymer of molecular weigh...

For a polymer solution, the dependence of viscosity $(\eta)$ on shear rate $(\dot{\gamma})$ is described by the three-parameter Carreau model given by\[\eta=\eta_{0}\left...

The dilute solution viscometry data for two samples of a polymer with two different molecular weights are shown in the figure, where $\eta_{s p} / c$ has been plotted aga...

The linear viscoelastic behaviour of a polymer is described by the Kelvin-Voigt model consisting of a spring element of elastic modulus $10$ MPa in parallel with a dashpo...

Q. 64An electrochemical cell consists of pure $\mathrm{Zn}$ electrode (anode) and a hydrogen electrode (cathode) in a dilute $\mathrm{Zn}^{+2}$ solution. The overall reac...

\begin{tabular}{|l|l|}Q. 112 & Consider the structure of a crosslinked polymer shown in the figure. From the \\options given, identify the monomers that are used in the s...

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

\begin{tabular}{|c|c|c|c|c|}\hline \multirow[t]{3}{*}{ Q. 114} & \multicolumn{4}{|c|}{\begin{tabular}{l}A high molecular weight polymer passes through different zones fro...

\begin{tabular}{|c|c|c|c|c|}\hline \multirow[t]{6}{*}{ Q. 116} & \multicolumn{4}{|c|}{\begin{tabular}{l}Among the options given, identify the correct match between the po...