【摘要】：聚乙烯醇(Poly(vinyl alcohol))是一種綜合性能優(yōu)異的水溶性高聚物。PVA的耐油、耐溶劑及氣體阻隔性能尤其出眾,在有機(jī)溶劑、食品藥品等包裝方面具有獨(dú)特優(yōu)勢。PVA高分子鏈上含有大量的活性羥基易形成大量的分子內(nèi)和分子間氫鍵,導(dǎo)致PVA的熔融溫度與其熱分解溫度相當(dāng)接近,熔融即分解,因而很難進(jìn)行熱塑加工。本文分別采用硅烷偶聯(lián)劑KH602與KH560對PVA進(jìn)行接枝改性,研究偶聯(lián)劑對PVA熔點(diǎn)的影響;分別采用天然大分子丹寧酸和明膠與PVA共混,研究其對PVA熱分解溫度的影響。同時,制備不同碳鏈長度的烷基酚聚氧乙烯醚磷酸酯(NP-4P、NP-10P、NP-15P),分別研究其對PVA熱穩(wěn)定性和熔點(diǎn)的影響,最終制備了寬熔融加工窗口的聚乙烯醇共混物。分別采用硅烷偶聯(lián)劑KH602和KH560對PVA進(jìn)行接枝改性,制備了PVA-g-KH602和PVA-g-KH560改性材料。研究結(jié)果表明:兩者的熔點(diǎn)分別由230℃降低至193℃和218℃,接觸角分別從49°提高至92°和73°,在降低熔點(diǎn)方面,KH602的效果明顯優(yōu)于KH560。改性后,PVA的拉伸強(qiáng)度從87.5 MPa分別降低至59.6 MPa和64.5 MPa,斷裂伸長率從156%分別提高到486%和338%。分別采用天然大分子丹寧酸(TA)和明膠(GEL)對PVA進(jìn)行共混,制備了PVA/TA和PVA/GEL共混物。研究結(jié)果表明:與純PVA相比,PVA/TA(7 wt%)和PVA/GEL(15wt%)共混物的熱分解溫度分別提高了103℃和87℃,熔點(diǎn)變化不大。隨著TA和GEL含量的逐漸增加,PVA/TA和PVA/GEL共混材料仍具有優(yōu)異的力學(xué)性能和透光率。分別采用不同碳鏈長度的磷酸酯類化合物(NP-4P、NP-10P、NP-15P)與PVA進(jìn)行共混,結(jié)果表明,三種磷酸酯類化合物均能有效提高PVA的熱分解溫度,降低熔點(diǎn)。其中PVA/NP-10P(5 wt%)共混物效果最好,熱分解溫度升至311℃,熔點(diǎn)降低至213℃。分別采用微分法、Kissinger法以及Ozawa法探討了PVA/NP-10P(5 wt%)與純PVA的熱降解動力學(xué)。結(jié)果表明,NP-10P可以有效地緩解PVA前期的熱分解速率,提高其熱穩(wěn)定性。力學(xué)性能結(jié)果表明,隨著NP-10P添加量的增多,PVA/NP-10P共混物的拉伸強(qiáng)度下降,斷裂伸長率增加。當(dāng)NP-10P的量為5 wt%時,PVA/NP-10P共混膜拉伸強(qiáng)度為72.2 MPa、斷裂伸長率為473%,透光率為85%。進(jìn)一步研究表明,在PVA-g-KH602中添加5 wt%的NP-10P制備寬熔融加工窗口PVA共混物,共混物熔點(diǎn)降低至185℃,熱分解溫度升為286℃,Td-Tm為101℃,易于熱塑加工。力學(xué)和透光率結(jié)果表明:PVA-g-KH602(7%)/NP-10P共混物薄膜的拉伸強(qiáng)度為64.3 MPa,斷裂伸長率為492%,透光率為74%,綜合性能優(yōu)異。
[Abstract]:Polyvinyl alcohol (Poly (vinyl alcohol) is a water-soluble polymer with excellent comprehensive properties. Its oil resistance, solvent resistance and gas barrier properties are especially outstanding in organic solvents. There are a lot of active hydroxyl groups in PVA macromolecular chain to form a large amount of intramolecular and intermolecular hydrogen bonds, which leads to the melting temperature of PVA is very close to its thermal decomposition temperature, that is to say, melting is decomposed. Therefore, it is difficult to carry out thermoplastic processing. In this paper, silane coupling agent KH602 and KH560 were used to graft PVA to study the effect of coupling agent on the melting point of PVA, and natural macromolecule tannic acid and gelatin were mixed with PVA to study the effect of coupling agent on the thermal decomposition temperature of PVA. At the same time, alkylphenol polyoxyethylene ether phosphate (NP-4P,NP-10P,NP-15P) with different carbon chain length was prepared, and its effects on thermal stability and melting point of PVA were studied respectively. Finally, polyvinyl alcohol blends with wide melting processing window were prepared. Silane coupling agents KH602 and KH560 were used to modify PVA to prepare PVA-g-KH602 and PVA-g-KH560 modified materials. The results show that the melting point of KH602 is decreased from 230 鈩，

本文編號：2447772