Functionalised oligomer

High compatibility of the additive with the polymer matrix usually extends performance but at the expense of extractability. Lack of extractability is of analytical concern, e.g. in case of functionalised oligomer and polymeric additives, grafted and reactive additive functionalities, and chemisorbed and absorbed additives. More generally, additive recovery levels significantly lower than the target level may arise from various situations ... 

Synthesis of compounds having an increased molecular weight represents the most natural way of producing physically persistent additives in demanding applications, which resist extraction or leaching. Pospisil [576] has described such functionalised oligomers and polymers as stabiliser systems for... 

The fragmentation in the MALDI-TOF MS experiment noted from the brominated polymer is less prevalent in this chlorinated material, but evidence for the lactone-ended oligomer (7) is still noted (see Figure 8). Evidence for the competing disproportionation mechanism is again provided by the presence of peaks proposed to be from unsaturated (8) and saturated (9) end-functionalised oligomer [10]. The data indicate that this disproportionation reaction is a minor termination pathway, as low intensity peaks are noted for 8 and 9 (as for 4 5 from the brominated analogue). 

Figure 28 MALDI-TOF mass spectrum from MDI/PPG polyurethane prepolymer. Peaks from functionalised oligomers are annotated with numbers corresponding to those described in the text.

Mono functionalised oligomers were synthesized by Ivonne Wallmann, in context of her Diploma thesis, University of Bonn. 

PospBilJ. Functionalised Oligomers and Polymers as Stabilizers for Conventional Polymers. Vol 101, pp. 65-168. 

Figure 7 Influence of the chemical structure of the functionalised oligomer on the cationic UV-curing of a vinyl ether-based resin (/ = 20 mW cm ). (-—) Postpolymerisation after a 0.7 s UV-exposure of the divinyl ether of triethyleneglycol.

The photosensitive resin consists either of a liquid functionalised oligomer, usually with acrylate groups, or a reactive polymer which will be applied as hot melt. There are two main classes of reactive polymers acrylic hot melts which may contain a tackifying monomer, and thermoplastic rubbers which predominantly block copolymers with polybutadiene or polyisoprene chains [3]. A radical-type photoinitiator is always needed to produce, upon UV-exposure, the free radicals that will initiate the polymerisation or cross-linking process. 

Apart from proteases, cutinases and lipases were demonstrated to hydrolyse PA. Hydrolysis of PA with a lipase (not further specified) was confirmed by using FTIR analysis and dye-binding assays [32]. Several reports have assessed the potential of cutinases for PA functionalisation, and a fungal cutinase from F. solani was successfully genetically engineered towards higher activity on a PA oligomer and PA [23-25]. 

The most abundant oligomer is the pentamer. These perfluorinated olefins are not reactive since the double bond is internal in the chain. However, the ICI Company [64] functionalises these alkenes by adding phenol onto the perfluorinated olefins ... 

It has also been possible to design a series of segmented functionalised copolymers (with polyether or polysiloxane segments) using a, co-dienyl tele-chelic oligomers for metathesis polycondensation [63]. 

Functionalising of Low-Molecular, Oligomer Dienes and Olefins with S, O-Containing Compounds... 

Relative viscosities of modified oligomers, determined by viscosimetry technique, are somewhat higher than the values of the respective initial oligomers (Table 5). The observed phenomenon allows to believe, that in the interaction of oligomers with phenols and element sulfur there occurs an increase in molecular weight due to the functionalised product generated. 

Various fluorinated aromatic nucleobases have been synthesised for PNA. As is found with similar fluorinated aromatic bases in DNA (section 1.3.3), they behave as universal bases with complementary DNA. PNA with a terminal 9-aminoacridine has been prepared to examine binding of monovalent ions. A Tio PNA oligomer was found to be sensitive to increasing the concentration of K(f) ions, but the presence of the terminal acridine significantly reduced the sensitivity. The incorporation of naphthalene diimide at the N-terminus of PNA stabilises DNA-PNA duplexes, whilst the bis-functionalised PNA (31) not only stabilises the duplex with DNA but also can be used to photocrosslink to DNA. The presence of the phosphonium ion in (31) aids mitochondrial location of the PNA. 

The functionalisation at the N1-position of 2 -deoxy-pseudouridine by Michael addition of methyl acrylate offered access to the phosphoramidites (61). The precursor to (61) was also functionalised as an amine derivative, which was transformed into the fluorescein-labelled phosphoramidites (62a-b). Fluorescent oligonucleotides were synthesised either from these latter building blocks or by post-synthetic modifications of oligomers containing the 2 -deoxy-pseudouridine-1 -propanoate units. ... 

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