# Polymeric and Crystalline Materials for Effective and Sustainable CO\({}_{2}\) Capture
## 3 Petroleum-Based Polymers
### Porous Organic Polymers  
POPs, or hyper-crosslinked polymeric materials constructed solely from organic covalent bonds, have emerged as versatile substances with a wide array of applications, including CO\({}_{2}\) capture. These materials are known by different names, including porous polymer networks (PPNs), porous organic frameworks (POFs), conjugated microporous polymers (CMPs), microporous organic polymers (MOPs), polymers of intrinsic microporosity (PIMs), hypercrosslinked polymers (HCPs), covalent triazine-based frameworks (CTFs), porous aromatic frameworks (PAFs), and crystalline covalent organic frameworks (COFs) [137]. For convenience, the term POPs broadly encompasses these materials. POPs offer several advantages for carbon capture applications. Firstly, their construction from relatively rigid monomers allows for the formation of pores with rigid walls, leading to permanent porosity comparable to the most porous materials. Notably, PPN-4 has demonstrated the highest surface area among POP materials published thus far [10]. Secondly, the synthesis of POPs draws from a wide range of modern bond-forming methodologies (i.e., Yamamoto coupling [10], boronic acid condensation [138], metal-catalyzed coupling [139], Schiff-base [140; 141], and Friedel-Craft alkylation [142]), resulting in numerous structural topologies and diversified porosities. Additionally, POPs, composed of lightweight elements, tend to have higher gravimetric carbon capture capacities. Moreover, their covalent bond nature confers high stability and exceptional chemical and water stability, enabling reusability. These properties, combined with large surface area, tunable pore size, high stability, and easy functionalization, make POPs ideal candidates for carbon capture [143; 144; 10]. As stated previously, covalent triazine frameworks (CTFs) have gained significant attention for their easy and scalable synthesis methods, as well as their tunable structures. A prevalent method for CTF preparation involves ionthermal trimerization of aromatic nitriles in the presence of ZnCl\({}_{2}\) at high temperatures, forming triazine linkages [146]. Alternative synthetic routes include acid-catalyzed and elemental sulfur-mediated approaches [147; 148]. With high surface area and thermal stability, CTFs' high nitrogen content renders them attractive for CO\({}_{2}\) capture and separation. Additionally, their chemical and physical stability make CTFs suitable as catalytic supports for various reactions, including CO\({}_{2}\) reduction [149]. However, challenges such as low conversion yield and selectivity have been observed despite promising catalytic activity. Recently, [PERSON] and coworkers have proposed the preparation of a charged covalent triazine framework based on cyanophenyl-substituted viologen dication [150]. The latter was then trimerized by an ionothermal reaction involving ZnCl\({}_{2}\) with better material porosity when the reaction was carried out at 500 \({}^{\circ}\)C. A CO\({}_{2}\) adsorption of 3 mmol g\({}^{-1}\) at 273 K and 1 bar was observed. Interestingly, the presence of charged functionalities in the CTFs also allowed the conversion of epoxide functional groups into cyclic carbonates. For instance, propylene oxide and epichlorohydrin were converted to their corresponding cyclic carbonates with a yield higher than 95%. [PERSON] and co-workers also studied the preparation of a triazine-based POP [151]. In a typical procedure, they reacted the chosen organic amine (i.e., ethylene diamine, triethylenediamine, or \(p\)-phenylenediamine) with 2,4,6-trichloro-1,3,5-triazine under basic conditions, affording the triazine-based POP (cCFTs) (Figure 6). These were then precarbonized at 200 \({}^{\circ}\)C, followed by a carbonization step at 500 \({}^{\circ}\)C to furnish the desired N-enriched porous carbons. In terms of performance, a CO\({}_{2}\) uptake of 0.93 mmol g\({}^{-1}\) at 273 K and 1 bar was noted.