Question 1

Which of the following best describes the mechanism of anionic chain polymerisation initiation for methyl cyanoacrylate?

Accepted Answer

Initiation occurs via a nucleophilic attack by a strong base, forming a carbanion stabilized by resonance with the cyano group.

Question 2

Why are electron-withdrawing groups (EWG) important in anionic polymerisation of vinyl monomers?

Accepted Answer

They stabilize the carbanion formed during propagation via resonance or inductive effects.

Question 3

Which solvent would most likely result in the highest rate of anionic styrene polymerisation, based on dielectric constant?

Accepted Answer

1,2-dimethoxyethane ($$\varepsilon = 5.5$$, $$k_p = 1900)$$

Question 4

Which of the following is NOT a suitable solvent for anionic polymerisation?

Accepted Answer

Dichloromethane ($$\mathrm{CH_2Cl_2})$$

Question 5

What is the main advantage of living polymerisation compared to conventional chain-growth polymerisation?

Accepted Answer

Predictable polymer molar masses and narrow dispersity due to absence of chain-breaking reactions.

Question 6

Which equation correctly relates the degree of polymerisation ($$DP) to $$monomer conversion ($$p$$), initial monomer amount ($$M_0$$), and initial initiator amount ($$I_0) in $$living polymerisation?

Accepted Answer

$$DP = \frac{p \cdot M_0$}{I_0$}$$

Question 7

Which of the following is a typical application of anionic polymerisation?

Accepted Answer

Production of styrene-butadiene-styrene (SBS) thermoplastic elastomers.

Question 8

What is the primary reason for spontaneous termination in anionic polymerisation at low temperatures?

Accepted Answer

Hydride elimination is reduced at temperatures below $$0^\circC.$$

Question 9

Which catalyst system is used for the production of high-density polyethylene (HDPE) via coordination polymerisation?

Accepted Answer

Ziegler-Natta (Ti/Al system)

Question 10

Which property distinguishes HDPE from LDPE?

Accepted Answer

HDPE has higher crystallinity and melting temperature due to lower branching.

Question 11

Which of the following is a key requirement for achieving living anionic polymerisation?

Accepted Answer

Absence of impurities and fast, reversible transfer or termination reactions.

Question 12

Which polymer is produced by ring-opening polymerisation (ROP) of lactide?

Accepted Answer

Poly(lactic acid) (PLA)

Question 13

What is the industrial catalyst used for the ROP of cyclic esters such as lactide?

Accepted Answer

Sn(Oct)$$_2$$

Question 14

Which of the following statements about superabsorbent polymers (SAP) is correct?

Accepted Answer

SAPs are typically cross-linked polyacrylates synthesized via radical polymerisation.

Question 15

Which of the following is a limitation of conventional chain-growth polymerisation compared to living polymerisation?

Accepted Answer

Unpredictable molar masses and broad dispersity due to chain-breaking reactions.

Question 16

Which mechanism is responsible for the formation of block copolymers in living polymerisation?

Accepted Answer

Sequential addition of different monomers to active chain ends.

Question 17

Which of the following is a typical side-reaction in anionic polymerisation that can limit polymer molar mass?

Accepted Answer

Intermolecular nucleophilic substitution (SN) with the monomer.

Question 18

Which property of poly(lactic acid) (PLA) makes it attractive for sustainable applications?

Accepted Answer

PLA is bio-based and industrially compostable.

Question 19

Which factor is most important for controlling tacticity in coordination polymerisation of polyolefins?

Accepted Answer

The coordination sphere of the metal catalyst, including ligands.

Question 20

Which equation correctly relates the number-average molar mass ($$M_n) to $$the degree of polymerisation ($$DP) $$and monomer molar mass ($$M_0$$)?

Accepted Answer

$$M_n = DP \cdot M_0$

Chain-Growth Polymerisation: Anionic, Coordination, and Living Polymerisation

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