## 1 Introduction
Butyl sealants are widely used in the glazing industry, particularly between glass and aluminum. These tapes can be compressed by 20-30% and have a service life of 10-20 years [12,13]. Polyisobutylene (PIB) as a homopolymer is permanently tacky. Due to its natural tackiness, it is self-healing. PIB is a transparent polymer with elastomeric properties, although it exhibits a much greater tendency to creep than most unvulcanized rubbers [4]. It is most commonly used as an additive to other binders or tapes, mainly of the butyl type. One possible solution to the problem of sealant softening at high temperatures, such as those reached by roofs during summer (90-100 \({}^{\circ}\)C), is crosslinking by the addition of a cross-linkable rubber component [7], crosslinking during compounding [14,15], or a combination of the aforementioned approaches [15,16]. Additionally, the use of siloxane compounds in the blend could improve adhesion to ceramic substrates. By using vinyltrimethoxysilane (VTMS) in compositions based on IIR and ethylene-vinyl acetate (EVA) copolymer, it has been shown that the improvement in binder properties results from the chemical interaction between EVAC and VTMS, forming semi-permeable network structures [7]. Thermoplastic binders based on IIR, containing polyethylene (PE) and ethylene-vinyl acetate (EVA) copolymer, are also used. These binders offer higher strength and a higher working temperature compared to non-vulcanized binders based on IIR [17]. In contrast to crosslinked binders based on reactive oligomers, where the required strength and adhesive properties are achieved only after full curing (typically after 24 h or more), these binders can be used immediately after application and cooling [7]. Additives  
A typical thermoplastic sealant consists of an elastomer [18], fillers [19; 20], plasticizers [6; 21], resins [22], technological additives (antioxidants), and functional additives that modify its properties [4; 7; 11] and behavior in different pH conditions [23]. The role of technological additives in binders is to control viscosity during processing, but their inclusion often leads to increased strength and adhesive properties, as well as expanding the working temperature range. Hydrocarbon resins, rosin derivatives, and bituminous substances are commonly used as additives in unvulcanized sealants. These compounds exhibit multifunctional properties: they enhance strength and adhesion to substrates while effectively reducing viscosity during processing and raising the working temperatures of the binders (80-100 \({}^{\circ}\)C) [14; 15; 16]. Organosilicon compounds present a promising approach for enhancing both the adhesion of sealants to common building substrates and the internal cohesion of the sealant matrix. While the application of organosilicon compounds as crosslinking coagents is well-established in static vulcanization systems, this study explores their potential for creating thermoplastic semi-interpenetrating networks (semi-IPNs) composed of mutually soluble polymers as well as determining the impact of adding organosilicon compounds on the change in the mechanical and processing properties of butyl-based sealing compounds, particularly under increased humidity conditions. This work presents, for the first time, the application of silanes with various functional groups, such as -SH, -NH\({}_{2}\), -CH=CH\({}_{2}\), and CH\({}_{2}\)(O)CHCH\({}_{2}\), to elastomeric sealant blends containing butyl rubber (IIR) and polyisobutylene (PIB) and evaluates their influence on the rheological and mechanical properties. The conducted research holds significant practical importance as it demonstrates that the modification of rubber sealants with functionalized silanes enables the development of materials with optimized properties, such as higher cohesion, improved delamination resistance, and enhanced processability. These characteristics make the findings directly applicable to the production of modern, more durable sealants.