Mechanical properties and morphology of impact modified polypropylene-wood flour composites

Oksman, Kristiina; Clemons, Craig M.

doi:10.1002/(sici)1097-4628(19980228)67:9<1503::aid-app1>3.0.co;2-h

Cited by 409 publications

(316 citation statements)

References 6 publications

(6 reference statements)

Supporting

Mentioning

282

Contrasting

Unclassified

Order By: Relevance

“…Outra consideração importante para a eficiência de reforçamento consiste na geração de zonas de trans-cristalinidade na interfase que depende do teor de MAH no compatibilizante e determina as condições de co-cristalização entre o PP e PP-MAH. Aspectos conflitantes sobre as condições de ocorrência de transcristalinidade nesses sistemas ainda exigem pesquisas mais aprofundadas [9,10,22] .…”

Section: Estudos De Compatibilização De Compósitos Termoplásticos Comunclassified

Compósitos termoplásticos com madeira

et al. 2003

View full text Add to dashboard Cite

Resumo: Dentre muitas fibras naturais de interesse tecnológico, o resíduo de madeira substitui com vantagens as cargas e reforços tradicionalmente empregados em compostos e compósitos poliméricos, particularmente os de origem mineral, tais como talco, CaCO 3 e fibra de vidro. A tecnologia dos chamados Wood-Plastic Composites (WPC´s) envolve conceitos de compatibilidade e processabilidade e apresenta grandes desafios tecnológicos para a formulação e estabilização da mistura devido à baixa estabilidade térmica da celulose. Muitos dos avanços tecnológicos em WPC's dependem de uma análise criteriosa das características físicas de seus componentes e das condições de processamento do sistema, particularmente aspectos relacionados a sua compatibilização. No presente trabalho são apresentados estudos sobre a reatividade do polipropileno modificado com anidrido maleico (PP-MAH) utilizado como compatibilizante em compósitos termoplásticos de polipropileno com farinha de madeira. A influência da carga celulósica e a eficiência do compatibilizante nas propriedades reológicas, térmicas, mecânicas e morfológicas do sistema foi avaliada através de medidas de rigidez, grau de cristalinidade, temperatura de cristalização e fusão cristalina levando-se em conta as características da resina, a distribuição granulométrica e o teor de umidade da farinha de madeira. Observou-se que os compósitos compatibilizados com PP-MAH apresentaram ganhos significativos de rigidez em relação aos compósitos não-modificados independentemente do tipo de farinha de madeira empregada. As propriedades térmicas do polímero mostraram-se sensíveis à distribuição granulométrica e algumas composições apresentaram tendência ao escurecimento e à elevação da temperatura de cristalização do polímero na presença do reforço celulósico. Imagens obtidas por microscopia eletrônica de varredura ilustram o molhamento da fibra celulósica pela resina termoplástica quando na presença do compatibilizante indicando a possível ocorrência de reações de esterificação na interface polímero-madeira. Palavras-Chave: Compósitos termoplástico-celulósicos, tecnologia polímero-madeira, compatibilização, reometria de torque, análise térmica. Wood-Plastic CompositesAbstract: Wood waste fibers (WWF), mostly known as wood flour, can replace mineral fillers such as talc, CaCO 3 and fiberglass in the reinforcement of thermoplastics with great advantage. Wood-plastics composites (WPC's) technology includes concepts of compatibility and processing and yet presents technical challenges in grade formulation and stabilisation of the composite system. Owing to thermal constraints in wood flour processing, commodities such as polyolefins (PP, PEAD/PEBD), styrenics (PS e HIPS) and vinyls (PVC) represent the bulk of the thermoplastics used in WPC's applications. In the present work, a brief overview of the latest developments in WPC's processing technology is discussed in the light of technical characteristics and performance of this novel class of thermoplastics composites in emerging applications...

show abstract

Section: Estudos De Compatibilização De Compósitos Termoplásticos Comunclassified

Compósitos termoplásticos com madeira

et al. 2003

View full text Add to dashboard Cite

show abstract

“…Poor adhesion means that on processing of the composites the unmodified lignocellulose components show a tendency toward aggregation as a consequence of the intermolecular interactions between the filler molecules [7]. For this reason many authors have been searching for methods of chemical or physical modifications of the components [8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Influence of cellulose polymorphs on the polypropylene crystallization

Borysiak

2013

J Therm Anal Calorim

View full text Add to dashboard Cite

Results of the hitherto research work on alkalisation of lignocellulosic materials have been much divergent. In view of the above, the subject of this study is mercerization of cellulose from pine wood. This choice of the subject permitted observation of transformation of cellulose I to cellulose II with no participation of other components of lignocellulosic materials. According to X-ray results, during mercerization the isolated cellulose was easily (completely) transformed into cellulose II variety, while the pine wood was converted more slowly to cellulose II polymorphs. Therefore, it could be concluded that the presence of lignin and hemicelluloses in wood prevented the transformation from cellulose I to II. The main objective of this research was to establish the effect of cellulose varieties on the nucleation ability of different fillers by using differential scanning calorimetry (DSC) and polarizing microscopy. The nucleating effect of the fillers occurs only in the presence of cellulose I variety. In contrast, the presence of cellulose II variety seems to practically eliminate the nucleating effect of the fillers. Moreover, nucleation of the mercerized wood (mixture of cellulose I and II) can be also observed, but this effect is not strong. It should be emphasised that as yet no correlation has been reported between the quantitative composition of cellulose polymorphic forms (appearing not only in wood, but in cellulose isolated from wood as well) and the nucleation ability of lignocellulosic fillers.

show abstract

“…When there is good adhesion between the filler and the matrix, a significant decrease in elongation at break can be expected even at small filler loading levels. In the case of poor adhesion, the decrease in elongation at break is expected to be more gradual (Oksman and Clemons 1998). This study's composites containing coupling agent have been proven to exhibit improved dispersion and are expected to exhibit improved adhesion at the particle/matrix interface as proposed in the previously discussed Halpin-Tsai comparison plots.…”

Section: Impp_sa9100_xgnp5mentioning

confidence: 71%

Exfoliated graphite nanoplatelet-filled impact modified polypropylene nanocomposites: influence of particle diameter, filler loading, and coupling agent on the mechanical properties

et al. 2013

View full text Add to dashboard Cite

Exfoliated graphite nanoplatelets (xGnP)-filled impact-modified polypropylene (IMPP) composites were prepared at 2, 4, 6, and 8 wt % xGnP with and without the addition of a coupling agent and manufactured using melt mixing followed by injection molding. The coupling agent used in this study was polypropylene-graft-maleic anhydride (PP-g-MA). The nanoparticles used were xGnP with three different sizes: xGnP 5 has an average thickness of 10 nm, and an average platelet diameter of 5 lm, whereas xGnP 15 and xGnP 25 have the same thickness but average diameters are 15 and 25 lm, respectively. Test results show that nanocomposites with smaller xGnP diameter exhibited better flexural and tensile properties for both neat and compatibilized composites. For composites containing a coupling agent, tensile and flexural modulus and strength increased with the addition of xGnP. In the case of neat composites, both tensile and flexural modulus and strength decreased at higher filler loading levels. Increasing xGnP loading resulted in reduction of elongation at break for both neat and composites containing coupling agent. Explanation of this brittle behavior in a nanoplatelet-filled IMPP is presented using scanning electron microscopy and transmission electron microscopy.

show abstract

Mechanical properties and morphology of impact modified polypropylene-wood flour composites

Cited by 409 publications

References 6 publications

Compósitos termoplásticos com madeira

Compósitos termoplásticos com madeira

Influence of cellulose polymorphs on the polypropylene crystallization

Exfoliated graphite nanoplatelet-filled impact modified polypropylene nanocomposites: influence of particle diameter, filler loading, and coupling agent on the mechanical properties

Contact Info

Product

Resources

About