Search results for "Polyolefins"
showing 7 items of 17 documents
Advanced ultra-high molecular weight polyethylene/antioxidant-functionalized carbon nanotubes nanocomposites with improved thermo-oxidative resistance
2015
Multiwalled carbon nanotubes (CNTs) functionalized with hindered phenol moieties are dispersed in ultra-high molecular weight polyethylene (UHMWPE), and the stabilizing action of the antioxidant (AO) functionalized CNTs (AO-f-CNTs) is studied through a combination of rheological and spectroscopic (FT-IR) analyses. The effectiveness of two alternative compounding methods, namely hot compaction (HC) and melt mixing (MM), is compared. The combination of high temperature and mechanical stress experienced during MM brings about noticeable degradation phenomena of the matrix already in the course of the compounding step. Differently, the milder conditions of the HC process preserve the stability …
Poliolefiny i środowisko
2006
Przedstawiono znaczenie, rozwój metod otrzymywania, kierunki zastosowania i perspektywy rozwoju poliolefin (głównie polietylenu i polipropylenu), materiałów dominujących w światowej produkcji i zużyciu tworzyw sztucznych. Scharakteryzowano oddziaływania tych polimerów na środowisko, kolejno w etapie ich wytwarzania, wykorzystywania i utylizacji odpadów poużytkowych.
Oxazoline functionalization of polyethylenes and their blends with polyamides and polyesters
2001
The compatibilization of blends of polyamide-6 (PA6) with linear low density polyethylene (LLDPE) and of poly(ethylene terephthalate) (PET) with high density polyethylene (HDPE), by functionalization of the polyethylenes with oxazoline groups was investigated. Chemical modification of LLDPE and HDPE was carried out by melt free radical grafting with ricinoloxazoline maleinate. Blends preparation was made either with a two-steps procedure comprising functionalization and blending, and in a single step in which the chemical modification of polyethylene with the oxazoline monomer was realized in situ, during blending. The characterization of the products was carried out by FTIR spectroscopy an…
Protection of high-density polyethylene-silicon composites from ultraviolet-visible photodegradation
2017
[EN] The extent of the ultraviolet¿visible (UV¿vis) photoirradiation effect on high-density polyethylene (HDPE) and HDPE¿sili-con (Si) composites is reported in terms of the addition of Si microparticles at contents of 0.1, 1, and 5 wt %. A standard acceleratedUV-vis exposure was applied over 2750 h, corresponding to 22 months in Florida. Thermogravimetry, differential scanning calorimetry,and Fourier transform infrared spectroscopy were used as reliable techniques for monitoring the quality of the HDPE-Si composites. Theincreasing addition of Si microparticles delayed the photodegradation of the HDPE¿Si composites. Because of their strong light-scattering effects, Si microparticles blocked…
Jauni viedie materiāli no multifāzu polimēru kompozīcijām, to fizikāli-mehānisko, deformatīvo un struktūras īpašību izmaiņas jonizējošā starojuma un …
2014
Promocijas darbā pētītas poliolefīnu – multifāzu kompozīcijas ar elastomēriem un šķērssaistīšanās promotoriem. Izvērtēta radiācijķīmiskās modificēšanas un lielas indukcijas magnētiskā lauka (B = 1,0-1,7 T) ietekme uz pētīto kompozītsistēmu stiprības-deformācijas, struktūras īpašībām, kā arī novērtēta magnētiskā lauka un jonizējošā starojuma mijiedarbības ietekme uz poliolefīnu makromolekulu šķērssaistīšanās efektivitāti. Iegūtas jaunas teorētiskas un praktiskas atziņas par radiācijķīmiski modificētu poliolefīnu multifāzu kompozīciju ekspluatācijas īpašībām, kas ļāva radīt jaunus uz polipropilēna bāzētus termonosēdmateriālus.
Novel strategic approach for the thermo- and photo- oxidative stabilization of polyolefin/clay nanocomposites
2017
Polyolefin/clay nanocomposites were prepared by melt mixing and their oxidative stability was studied under long-term thermo- and photo-oxidative test conditions in the absence and presence of a modified organo montmorillonite clay (OM-MMt) containing a chemically-bound hindered phenol antioxidant function, (AO)OM-Mt. It was found that nanocomposites based on both polyethylene (PE) and polyethylene-grafted-maleic anhydride (PEgMA) containing the (AO)OM-Mt gave a higher oxidative stability, along with better clay dispersion, compared to analogous PE or PEgMA-based nanocomposites containing an added (free) conventional antioxidant with a similar hindered phenol function (using the commercial …