# Synthesis and Porous Structure Characteristics of Allyl Methacrylate/Divinylbenzene Polymers
## 1 Introduction  
Porous polymers have been the subject of intensive investigations for a long time. The research was driven by the progress of many technologies, such as technologies associated with water purification, wastewater treatment, and environmental protection. Porous polymers have been found to be applicable in various branches of science, including organic chemistry (as catalysts, carriers for catalysts, and scavengers in combinatorial chemistry) and analytical chemistry. In analytical chemistry, porous polymers were used as stationary phases in gas chromatography and liquid chromatography, and they were also applied in the sample preparation processes such as preconcentration and solid phase extraction. All of the above applications are possible due to the sorptive properties of those polymers. At first, porous polymers were mostly obtained from styrene and divinylbenzene. Their porosity was controlled by the addition of so-called porogens (inert solvents) to the polymerization mixture, but the chemical character of the surface was always the same: hydrophobic. So, they were efficient in the removal of hydrophobic water contaminants. The problem (low percentage of removal, especially under competitive conditions) was the effectivity of the removal of more hydrophilic and polar compounds from aqueous solutions. Therefore, there was a trend in polymer chemistry focused on the synthesis of porous polymers with greater affinity towards polar and hydrophilic sorbates. Since the removal of pollutants requires the interaction of the molecules with the porous polymer surface, it was necessary to modify the surface of porous polymers by adding functional groups that could provide stronger interactions, such as dipole-dipole interactions and hydrogen bonding [1, 2]. Such functional polar groups in the structure of the porous polymer are influencing the capacity of the sorbent and the selectivity of the sorption process [3]. Chemical groups can beintroduced into polymeric adsorbents either through polymerization of suitable functional monomers or by chemically modifying polymeric precursors [4]. Incorporating functional groups onto the surface of styrene/divinylbenzene copolymers enhances surface polarity and hydrophilicity, thereby improving the sorption of polar sorbates. There are studies involving the introduction of functional groups like o-carboxybenzoyl[5; 6], acetyl [7], benzoyl [8], and hydroxymethyl [9] groups onto the surface of styrene-divinylbenzene copolymers. The researchers observed that these modifications significantly increased the recovery of hydrophilic molecules. There are also studies for the functionalization of styrene/divinylbenzene by modifying it via etylenediamine [10], toluene [11], and 2-pyrrolidone or trimellitic anhydride [12]. Their sorptive properties towards the polar sorbates were improved compared to unmodified styrene/divinylbenzene. Interesting examples of styrene/divinylbenzene modifications were reviewed in ref. [13]. The authors presented the use of unreacted (remained in the structure of crosslinked polymer) vinyl bonds in some reactions leading to polar sorbents [13]. Another method for obtaining polar sorbents is copolymerization of the appropriate monomers containing suitable functional group(s) like commercial Amberlite XAD-7 and Chromosorb 104 functionalized with ester (from methyl methacrylate) and nitrile (from acrylonitrile) groups, respectively. 4-vinylpyridine/divinylbenzene [14], N-vinylimidazole/divinylbenzene [15], acrylonitrile/divinylbenzene [16; 17; 18], and methacrylonitrile/divinylbenzene [19] were also synthesized for enhancing the sorptive properties towards polar molecules. It was concluded that a large specific surface area and, at the same time, a large proportion of strongly polar functional groups are equally important [20; 19; 21]. In our previous study [4], cyanomethyl styrene (CMSt) was copolymerized with DVB.